<SEC-DOCUMENT>0001628280-20-016044.txt : 20201109
<SEC-HEADER>0001628280-20-016044.hdr.sgml : 20201109
<ACCEPTANCE-DATETIME>20201109090029
ACCESSION NUMBER:		0001628280-20-016044
CONFORMED SUBMISSION TYPE:	10-Q
PUBLIC DOCUMENT COUNT:		80
CONFORMED PERIOD OF REPORT:	20200930
FILED AS OF DATE:		20201109
DATE AS OF CHANGE:		20201109

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mersana Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001442836
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		10-Q
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38129
		FILM NUMBER:		201296311

	BUSINESS ADDRESS:	
		STREET 1:		840 MEMORIAL DRIVE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		617-498-0020

	MAIL ADDRESS:	
		STREET 1:		840 MEMORIAL DRIVE
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MERSANA THERAPEUTICS INC
		DATE OF NAME CHANGE:	20080813
</SEC-HEADER>
<DOCUMENT>
<TYPE>10-Q
<SEQUENCE>1
<FILENAME>mrsn-20200930.htm
<DESCRIPTION>10-Q
<TEXT>
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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGFibGU6NzM3ZWJmZTUyZmFkNDJkYThjOGU3NTFmYjY0MThiNzcvdGFibGVyYW5nZTo3MzdlYmZlNTJmYWQ0MmRhOGM4ZTc1MWZiNjQxOGI3N18wLTAtMS0xLTA_bcbdc465-b97a-412f-ac34-fe5e6fdb91ae">Delaware</ix:nonNumeric></span></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:EntityTaxIdentificationNumber" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGFibGU6NzM3ZWJmZTUyZmFkNDJkYThjOGU3NTFmYjY0MThiNzcvdGFibGVyYW5nZTo3MzdlYmZlNTJmYWQ0MmRhOGM4ZTc1MWZiNjQxOGI3N18wLTEtMS0xLTA_21ddfc0e-f8a5-4b46-870c-8cba4282523a">04-3562403</ix:nonNumeric></span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(State or other jurisdiction of<br/>incorporation or organization)</span></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(I.R.S. Employer<br/>Identification No.)</span></td></tr></table></div><div style="text-align:center"><span><br/></span></div><div style="margin-bottom:6pt;text-align:center"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:26.041%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td></tr></table></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:EntityAddressAddressLine1" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGV4dHJlZ2lvbjowYTk2MjQ5ZTEyODA0Zjc2OTE1OGMyYzVjMGM0YzVkY18yMTQ0_1a2d2bdb-28d4-4bb8-a6aa-a9f2e76485f1">840 Memorial Drive</ix:nonNumeric> <ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:EntityAddressCityOrTown" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGV4dHJlZ2lvbjowYTk2MjQ5ZTEyODA0Zjc2OTE1OGMyYzVjMGM0YzVkY18yMTQ1_8889625c-48bd-45d0-9454-a5dffb3c1d5c">Cambridge</ix:nonNumeric>, <ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:EntityAddressStateOrProvince" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGV4dHJlZ2lvbjowYTk2MjQ5ZTEyODA0Zjc2OTE1OGMyYzVjMGM0YzVkY18yMTUx_b807fa80-f696-49a0-bd77-eb860cfeee6d">MA</ix:nonNumeric> <ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:EntityAddressPostalZipCode" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGV4dHJlZ2lvbjowYTk2MjQ5ZTEyODA0Zjc2OTE1OGMyYzVjMGM0YzVkY18yMTUy_2bbf5807-df88-44e1-b586-fd3c4d8f9819">02139</ix:nonNumeric></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(Address of principal executive offices)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(Zip Code)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:CityAreaCode" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGV4dHJlZ2lvbjowYTk2MjQ5ZTEyODA0Zjc2OTE1OGMyYzVjMGM0YzVkY18yMTQ2_00ef36a1-4c31-43f3-91d4-a1851daa1133">617</ix:nonNumeric>) <ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:LocalPhoneNumber" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGV4dHJlZ2lvbjowYTk2MjQ5ZTEyODA0Zjc2OTE1OGMyYzVjMGM0YzVkY18yMTU0_c397d748-1f7a-41dd-91a2-9943ca89bf93">498-0020</ix:nonNumeric></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(Registrant&#8217;s telephone number, including area code)</span></div><div style="margin-bottom:6pt;text-align:center"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:26.041%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr style="height:3pt"><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td></tr></table></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Securities registered pursuant to Section 12(b) of the Act:</span></div><div style="margin-bottom:6pt;text-align:center"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.869%"><tr><td style="width:1.0%"></td><td style="width:32.928%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:21.455%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:42.317%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="border-left:1pt solid #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Title of each class</span></td><td colspan="3" style="border-left:1pt solid #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Trading symbol(s)</span></td><td colspan="3" style="border-left:1pt solid #000000;border-right:1pt solid #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Name of each exchange on which registered</span></td></tr><tr><td colspan="3" style="border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:Security12bTitle" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGFibGU6OWMyOGQyNzNjZDVlNDc2NGFkNjMxN2I2OTE0OGJjMTQvdGFibGVyYW5nZTo5YzI4ZDI3M2NkNWU0NzY0YWQ2MzE3YjY5MTQ4YmMxNF8xLTAtMS0xLTA_0fcb6404-32dd-413d-a985-f89f32fae7ea">Common Stock, $0.0001 par value</ix:nonNumeric></span></td><td colspan="3" style="border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="dei:TradingSymbol" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGFibGU6OWMyOGQyNzNjZDVlNDc2NGFkNjMxN2I2OTE0OGJjMTQvdGFibGVyYW5nZTo5YzI4ZDI3M2NkNWU0NzY0YWQ2MzE3YjY5MTQ4YmMxNF8xLTEtMS0xLTA_e28093c5-c8aa-4962-984f-9d1a992ddf34">MRSN</ix:nonNumeric></span></td><td colspan="3" style="border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" format="ixt-sec:exchnameen" name="dei:SecurityExchangeName" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xL2ZyYWc6MGE5NjI0OWUxMjgwNGY3NjkxNThjMmM1YzBjNGM1ZGMvdGFibGU6OWMyOGQyNzNjZDVlNDc2NGFkNjMxN2I2OTE0OGJjMTQvdGFibGVyYW5nZTo5YzI4ZDI3M2NkNWU0NzY0YWQ2MzE3YjY5MTQ4YmMxNF8xLTItMS0xLTA_65118ec7-5535-4960-88f8-dbdb19ab2e1a">The Nasdaq Global Select Market</ix:nonNumeric></span></td></tr></table></div><div style="margin-bottom:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Indicate by check mark whether the registrant (1)&#160;has filed all reports required to be filed by Section&#160;13 or 15 (d)&#160;of the Securities Exchange Act of 1934 during the preceding 12&#160;months (or for such shorter period that the registrant was required to file such reports), and (2)&#160;has been subject to such filing requirements for the past 90&#160;days. <ix:nonNumeric 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Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on our current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, our clinical results and other future conditions. The words &#8220;aim,&#8221; &#8220;anticipate,&#8221; &#8220;believe,&#8221; &#8220;contemplate,&#8221; &#8220;continue,&#8221; &#8220;could,&#8221; &#8220;estimate,&#8221; &#8220;expect,&#8221; &#8220;goal,&#8221; &#8220;intend,&#8221; &#8220;may,&#8221; &#8220;on track,&#8221; &#8220;plan,&#8221; &#8220;possible,&#8221; &#8220;potential,&#8221; &#8220;predict,&#8221; &#8220;project,&#8221; &#8220;seek,&#8221; &#8220;should,&#8221; &#8220;target,&#8221; &#8220;will,&#8221; &#8220;would&#8221; or the negative of these terms or other similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.</span></div><div style="margin-bottom:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">These forward-looking statements include, among other things, statements about:</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the initiation, cost, timing, progress and results of our current and future research and development activities and preclinical and clinical studies;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the adequacy of our inventory of XMT-1536 and XMT-1592 to support our ongoing clinical studies, as well as the outcome of planned manufacturing runs;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the timing of, and our ability to obtain and maintain, regulatory approvals for our product candidates;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">unmet need of ovarian cancer and non-small cell lung cancer;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">our ability to quickly and efficiently identify and develop additional product candidates;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">our ability to advance any product candidate into, and successfully complete, clinical studies;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">our intellectual property position, including with respect to our trade secrets;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the potential benefits of strategic partnership agreements and our ability to enter into selective strategic partnerships;</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">our estimates regarding expenses, future revenues, capital requirements, the sufficiency of our current and expected cash resources and our need for additional financing; and</span></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the potential impact of the ongoing COVID-19 pandemic.</span></div><div style="margin-bottom:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in our Annual Report on Form 10-K for the year ended December 31, 2019 and our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2020, particularly in the &#8220;Risk Factors&#8221; sections, that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.</span></div><div style="margin-bottom:9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In addition, while we expect that the COVID-19 pandemic might adversely affect our preclinical and clinical development efforts, business operations and financial results, the extent of the impact and the value of and market for our common stock will depend on future developments that are highly uncertain and cannot be predicted with confidence at this time, such as the ultimate duration of the pandemic, travel restrictions, quarantines, physical distancing and business closure requirements in the U.S. and in other countries, and the effectiveness of actions taken globally to contain and treat the disease.</span></div><div style="margin-bottom:9pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The forward-looking statements contained herein represent our views as of the date of this Quarterly Report on Form 10-Q. We anticipate that subsequent events and developments will cause our views to change. You should, therefore, not rely on these forward-looking statements as representing our views as of any date subsequent to the date of this Quarterly Report on Form 10-Q.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">2</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10"></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">TABLE OF CONTENTS</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:93.611%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:4.189%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Page</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_13">PART&#160;I&#160;&#8211; FINANCIAL INFORMATION</a></span></div></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_16">&#160;Item 1. Financial Statements (unaudited)</a></span></div></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:24.75pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_19">Condensed Consolidated Balance Sheets as of </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_19">September</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_19"> 30, 2020 and December 31, 2019</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_19">4</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:24.75pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22">Condensed Consolidated Statements of Operations and Comprehensive </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22">Loss</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22"> for the three and </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22">nine</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22"> months ended </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22">September</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22"> 30, 2020 and 2019</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22">5</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:24.75pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25">Condensed Consolidated Statement of Stockholders&#8217; Equity for the three and </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25">nine</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25"> months ended </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25">September</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25">&#160;30, 2020 and 2019</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25">6</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:24.75pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28">Condensed Consolidated Statements of Cash Flows for the </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28">nine</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28"> months ended </a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28">September</a><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28"> 30, 2020 and 2019</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28">7</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_31">Notes&#160;to Condensed Consolidated Financial Statements</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_31">8</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_82">Item&#160;2. Management&#8217;s Discussion and Analysis of Financial Condition and Results of Operations</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_82">23</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_85">Item&#160;3. Quantitative and Qualitative Disclosures About Market Risk</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_85">34</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_88">Item&#160;4. Controls and Procedures</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_88">34</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_91">PART&#160;II&#160;- OTHER INFORMATION</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_91">36</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_94">Item&#160;1. Legal Proceedings</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_94">36</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_97">Item 1A. Risk Factors</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_97">36</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_100">Item&#160;6. Exhibits</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_100">36</a></span></div></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_103">Signatures</a></span></div></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="text-align:right"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:none" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_103">37</a></span></div></td></tr></table></div><div style="margin-bottom:12pt"><span><br/></span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">3</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_13"></div><hr style="page-break-after:always"/><div style="min-height:36pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">PART&#160;I&#160;&#8211; FINANCIAL INFORMATION</span></div><div style="margin-bottom:12pt"><span><br/></span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_16"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;1.&#160;Financial Statements</span></div><div style="margin-bottom:12pt"><span><br/></span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_19"></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Condensed Consolidated Balance Sheets</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash and cash equivalents</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashAndCashEquivalentsAtCarryingValue" scale="3" 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style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prepaid expenses and other current assets</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:PrepaidExpenseAndOtherAssetsCurrent" scale="3" 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfOS0zLTEtMS0w_aa92cf51-4f3f-4bc4-a2c5-af159b2ef40f">2,598</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other assets</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OtherAssetsNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTAtMS0xLTEtMA_4c59c111-b9d2-46e6-9fde-55b34a029004">2,153</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OtherAssetsNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTAtMy0xLTEtMA_3cda4395-1178-41ce-87af-66e88e1c5fe4">1,453</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total assets</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:Assets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTEtMS0xLTEtMA_3aa7f8b4-31e1-4c51-96b4-1638cb5c77dd">290,128</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:Assets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTEtMy0xLTEtMA_a2d96fca-56f4-4903-868f-0b8465252130">107,541</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Liabilities and stockholders&#8217; equity</span></td><td colspan="3" style="background-color:#cceeff;border-top:3pt double #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:3pt double #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current liabilities:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accounts payable</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccountsPayableCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTQtMS0xLTEtMA_e032ebd6-f5c3-49d1-b4cc-1012c291cce5">4,528</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccountsPayableCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTQtMy0xLTEtMA_b1b18c8c-79e5-491a-bd93-ef6236fecded">7,296</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued expenses</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccruedLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTUtMS0xLTEtMA_28f178fe-2ef9-48f1-ae08-cca241c3fb1e">11,173</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccruedLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTUtMy0xLTEtMA_59d7240d-dee8-4bb7-a4cb-4264b55a3a36">8,986</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiabilityCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTYtMS0xLTEtMA_018b5c9f-5e15-4c05-b031-b8baff344b46">3,998</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiabilityCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTYtMy0xLTEtMA_13d4a69c-803e-4281-9c60-fa663ad56173">4,815</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Operating lease liabilities</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OperatingLeaseLiabilityCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTctMS0xLTEtMA_22210cc9-85a7-440c-9397-b324af15e733">1,280</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OperatingLeaseLiabilityCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTctMy0xLTEtMA_7b849272-ffa7-436e-8e45-31538da46051">2,219</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Short-term debt</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:zerodash" name="us-gaap:LongTermDebtCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTgtMS0xLTEtMA_df487275-5583-488c-9948-2c0acd79c502">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:LongTermDebtCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTgtMy0xLTEtMA_d17fcfb0-2e1d-4ca4-8fc6-bb42dd0189ab">667</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other liabilities</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:OtherLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTktMS0xLTEtMA_38d9f915-dda3-49d5-b56c-41bbee655961">91</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:OtherLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMTktMy0xLTEtMA_109324a7-ed42-42e7-8870-8e5fff19db74">87</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total current liabilities</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjAtMS0xLTEtMA_e72796c8-d322-4ad2-9bf4-984335dd4be5">21,070</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjAtMy0xLTEtMA_b6365dff-3c21-4028-a430-10335288d6bc">24,070</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Operating lease liabilities</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OperatingLeaseLiabilityNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjEtMS0xLTEtMA_d86859b4-6b1f-4c5b-9bab-9269cba2d0a0">10,606</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:OperatingLeaseLiabilityNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjEtMy0xLTEtMA_ed22d66a-3067-4ba2-b458-4627a760d6f8">677</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Long-term debt, net</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LongTermDebtNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjItMS0xLTEtMA_85dab00f-ce82-4d4b-bee5-efec4a5feab5">4,944</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LongTermDebtNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjItMy0xLTEtMA_be922115-7120-4c4a-98ff-3000bbeacdad">4,201</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other liabilities</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:OtherLiabilitiesNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjMtMS0xLTEtMA_712cbf97-4679-4ff8-b64f-96df3017c55b">200</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:OtherLiabilitiesNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjMtMy0xLTEtMA_33fcc700-6bf8-4b56-afae-f8879eaaa896">275</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total liabilities</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:Liabilities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjQtMS0xLTEtMA_e6af448d-7fff-4875-bcde-72e5e21c816e">36,820</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:Liabilities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjQtMy0xLTEtMA_a7d83c3c-72b5-466f-a8c9-411070caf97c">29,223</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Commitments (Note&#160;11)</span></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" xsi:nil="true" name="us-gaap:CommitmentsAndContingencies" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjUtMS0xLTEtMA_7475f857-4d91-4720-a13b-2a3c6de3720a"></ix:nonFraction></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" xsi:nil="true" name="us-gaap:CommitmentsAndContingencies" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjUtMy0xLTEtMA_c82ed5cc-2a7c-497a-9948-b1c948d928a3"></ix:nonFraction></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stockholders' equity:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Preferred stock, $<ix:nonFraction unitRef="usdPerShare" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" name="us-gaap:PreferredStockParOrStatedValuePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzIx_ba4dfb2a-990e-43f9-aa56-5688490a2b4a"><ix:nonFraction unitRef="usdPerShare" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" name="us-gaap:PreferredStockParOrStatedValuePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzIx_fbde5c27-ed72-4ffc-8f78-35aa8f2008b1">0.0001</ix:nonFraction></ix:nonFraction> par value; <ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:PreferredStockSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzM1_6c387337-b149-4b4a-ac2f-b9b9518f9302"><ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:PreferredStockSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzM1_d683b7e5-c92c-4cd2-a4a9-30400647dcf8">25,000,000</ix:nonFraction></ix:nonFraction> shares authorized; <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" name="us-gaap:PreferredStockSharesIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzU3_0f260b56-536d-40e6-aaac-c7d0865418b1"><ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" name="us-gaap:PreferredStockSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzU3_4e8edfda-89d6-4446-8ed7-016764945e4b"><ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" name="us-gaap:PreferredStockSharesIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzU3_af8cc9e4-39a4-4caf-848c-91969e529899"><ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" name="us-gaap:PreferredStockSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMC0xLTEtMC90ZXh0cmVnaW9uOjcwMzE3OWZjNjE2MjQyZGY5ZTkyZjk1MWJjNGMzNmQxXzU3_be345e6b-548a-402b-8e7f-9324e547c22d">0</ix:nonFraction></ix:nonFraction></ix:nonFraction></ix:nonFraction> shares issued and outstanding at September&#160;30, 2020 and December&#160;31, 2019, respectively</span></div></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:zerodash" name="us-gaap:PreferredStockValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMS0xLTEtMA_21721dbb-c1f9-4273-8ae7-a585653c4eb5">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:PreferredStockValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjctMy0xLTEtMA_6a168d2b-7e30-480e-aa54-aad577cca339">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Common stock,$<ix:nonFraction unitRef="usdPerShare" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" name="us-gaap:CommonStockParOrStatedValuePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzE3_2c9b29b5-48d0-4bfa-b607-58bed36e259c"><ix:nonFraction unitRef="usdPerShare" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" name="us-gaap:CommonStockParOrStatedValuePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzE3_a65a0fbf-e509-4847-bd87-4fbb37d0014e">0.0001</ix:nonFraction></ix:nonFraction> par value; <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzMx_cc61edf2-778c-48a5-8594-4a945d2ae818"><ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzMx_f2f670f2-3016-4947-b70c-872949ca448c">175,000,000</ix:nonFraction></ix:nonFraction> shares authorized; <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzUz_6f5e9b22-265b-4ebf-aea3-5970e9589b47"><ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockSharesIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzUz_a5570e5c-86b4-4e86-9299-d021f9e0dbad">68,470,081</ix:nonFraction></ix:nonFraction> and <ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzYw_63d73e9b-7694-49cb-b106-334ea3dc459e"><ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockSharesIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMC0xLTEtMC90ZXh0cmVnaW9uOjQ2NjE5NTkzMTZkYTRkMTM4NGZlZTM1ZTQ3ODY0YmQwXzYw_d5ef67d7-55f8-4088-95e2-847d81025ee4">45,388,023</ix:nonFraction></ix:nonFraction>&#160;shares issued and outstanding at September&#160;30, 2020 and December&#160;31, 2019, respectively</span></div></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:CommonStockValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMS0xLTEtMA_3f8fb60e-c5d5-42a1-b5f8-4ce89ca9e771">7</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:CommonStockValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjgtMy0xLTEtMA_b38f5682-45c0-4cb9-a819-f23d06924948">5</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Additional paid-in capital</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdditionalPaidInCapitalCommonStock" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjktMS0xLTEtMA_240cde15-a861-464c-96e1-00bb82e2c971">504,876</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdditionalPaidInCapitalCommonStock" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMjktMy0xLTEtMA_ac9aa3b3-009e-4854-af34-8d1cac05a384">270,662</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accumulated other comprehensive income (loss)</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 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1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMzAtMy0xLTEtMA_1fc7b7e7-a2e5-4871-839c-d5ff55c77d60">25</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accumulated deficit</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:RetainedEarningsAccumulatedDeficit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMzEtMS0xLTEtMA_2de750de-19c3-4ea5-87db-b3ac68f3c9cc">251,575</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:RetainedEarningsAccumulatedDeficit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8xOS9mcmFnOjEyYjkyMzU4NGU3ZjQyMDZhNGY1NzAwMDc4ZTJmNGIxL3RhYmxlOmY0MDEzOTlmNjgwNDRhYjhiYmFmYmYyODAzYmZlM2ExL3RhYmxlcmFuZ2U6ZjQwMTM5OWY2ODA0NGFiOGJiYWZiZjI4MDNiZmUzYTFfMzEtMy0xLTEtMA_a1f7b14e-6202-4029-be72-d22a95876b77">192,374</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total stockholders&#8217; equity</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" 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style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_22"></div><hr style="page-break-after:always"/><div style="min-height:36pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Condensed Consolidated Statements of Operations and Comprehensive Loss</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:45.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.723%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfNi0xLTEtMS0w_214a1c19-a58f-4f59-8ee2-10068a1068c3">22,427</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" format="ixt:numdotdecimal" 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format="ixt:numdotdecimal" name="us-gaap:OperatingExpenses" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfNi01LTEtMS0w_1b797b64-789f-4bd6-8c7b-aa3ac2086511">60,167</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OperatingExpenses" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfNi03LTEtMS0w_298b6daf-99b4-428e-9ac8-852a5dcb2e6b">55,682</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other income (expense):</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Interest income</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" name="us-gaap:InvestmentIncomeInterest" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOC0xLTEtMS0w_d586e7eb-242a-4524-97dd-b5692bfd0011">19</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:InvestmentIncomeInterest" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOC0zLTEtMS0w_fcfef036-8ef8-4625-af89-24b026a4e905">608</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:InvestmentIncomeInterest" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOC01LTEtMS0w_ab6cd7af-490a-44e2-80da-3eaab8f7ab40">414</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:InvestmentIncomeInterest" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOC03LTEtMS0w_36ed9252-14d9-4b2d-b4af-99afbfeb38f4">1,785</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Interest expense</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" name="us-gaap:InterestExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOS0xLTEtMS0w_ff376a17-85d7-427e-935f-de793fdf2689">92</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:InterestExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOS0zLTEtMS0w_2ae5cc63-8dff-4bce-a35a-66eb027268eb">107</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:InterestExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOS01LTEtMS0w_59a86159-d434-4f36-88b7-0056e6002a38">267</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:InterestExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfOS03LTEtMS0w_5aebff21-4cc7-49e1-b881-b995d8d5ae92">146</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total other income (expense), net</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" sign="-" name="us-gaap:NonoperatingIncomeExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTAtMS0xLTEtMA_a159576b-b518-4372-aad1-a9412a3f34ce">73</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:NonoperatingIncomeExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTAtMy0xLTEtMA_33e1de0f-039b-414a-8d08-c49ab436d18a">501</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:NonoperatingIncomeExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTAtNS0xLTEtMA_7061a5cd-dbc2-4810-bb6a-655575e1c121">147</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:NonoperatingIncomeExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTAtNy0xLTEtMA_d058c7ec-4115-47f7-8808-3923a5df425b">1,639</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net loss</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTEtMS0xLTEtMA_472f6182-25fd-4f4a-b472-ce1368102ec4">22,489</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTEtMy0xLTEtMA_28c0a7e5-5bdd-4420-99f0-949a33eab24b">16,792</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTEtNS0xLTEtMA_d64666c4-db4c-483c-83ca-d27302b51730">59,203</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTEtNy0xLTEtMA_144c4e24-2004-47ee-8618-b29e8bb1d1c6">11,962</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other comprehensive loss</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unrealized gain (loss) on marketable securities</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" sign="-" name="us-gaap:OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTMtMS0xLTEtMA_3233c0c5-c0fb-4e7f-a5e2-efdbcfea97ca">2</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTMtMy0xLTEtMA_d0eb19cf-1fdd-4dd0-9e9a-f25e105cfe4b">17</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" name="us-gaap:OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTMtNS0xLTEtMA_60156515-a7df-4a01-b695-e9382657ceb6">25</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTMtNy0xLTEtMA_a2c938f7-12ed-473f-9aee-1c097478350d">36</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Comprehensive loss</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:ComprehensiveIncomeNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTQtMS0xLTEtMA_da963a9b-bcdb-4028-b383-f2e0fa02f06e">22,491</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:ComprehensiveIncomeNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTQtMy0xLTEtMA_79e8878e-1ee0-4df8-99da-441ef37f920b">16,775</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:ComprehensiveIncomeNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTQtNS0xLTEtMA_70db3c77-616a-478e-8b11-227ef52e3541">59,228</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:ComprehensiveIncomeNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTQtNy0xLTEtMA_39c0b36b-b63b-4840-99c9-ffa6e3da725b">11,926</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net loss attributable to common stockholders &#8212; basic and diluted</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtMS0xLTEtMA_369ac122-ebed-445c-adf8-8158559dccbe"><ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersDiluted" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtMS0xLTEtMA_391a8222-19e8-4a85-9313-0ab658df47a1">22,489</ix:nonFraction></ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtMy0xLTEtMA_3eacc82a-465b-4dd4-a412-58e74ca839f5"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersDiluted" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtMy0xLTEtMA_6660fed1-afad-4fc8-a585-6b9ca6345034">16,792</ix:nonFraction></ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtNS0xLTEtMA_76e23334-4b59-4a90-a741-1dd8abd52524"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersDiluted" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtNS0xLTEtMA_df0e54b4-b756-4679-9913-6fdd843abca9">59,203</ix:nonFraction></ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtNy0xLTEtMA_1ad46818-448e-4934-b022-7ba13464f565"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLossAvailableToCommonStockholdersDiluted" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTUtNy0xLTEtMA_c268e9da-7b1b-4212-af26-be56d2a9e329">11,962</ix:nonFraction></ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net loss per share attributable to common stockholders &#8212; basic and diluted</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usdPerShare" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="2" sign="-" name="us-gaap:EarningsPerShareBasicAndDiluted" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTYtMS0xLTEtMA_cd8bf7ba-c4c9-4492-95c8-04aa89c759cc">0.33</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usdPerShare" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="2" sign="-" name="us-gaap:EarningsPerShareBasicAndDiluted" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTYtMy0xLTEtMA_2e097e14-c717-4e1d-a715-a866c2626ffb">0.35</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usdPerShare" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="2" sign="-" name="us-gaap:EarningsPerShareBasicAndDiluted" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTYtNS0xLTEtMA_7da88b1c-7e2a-4ec3-8d9d-c45eb3fa413b">1.00</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usdPerShare" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="2" sign="-" name="us-gaap:EarningsPerShareBasicAndDiluted" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTYtNy0xLTEtMA_9e63d915-4ca8-4b39-bece-0bf62c5daa98">0.28</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Weighted-average number of shares of common stock used in net loss per share attributable to common stockholders &#8212; basic and diluted</span></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:WeightedAverageNumberOfSharesOutstandingBasic" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTgtMS0xLTEtMA_9ba46e65-7d1d-4467-a9e3-e174800d182a"><ix:nonFraction unitRef="shares" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTgtMS0xLTEtMA_ba0578cf-7848-40ec-abb9-6bb2bbb6e36f">68,419,192</ix:nonFraction></ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTgtMy0xLTEtMA_8c07a9b4-6319-47fe-836f-1db154a36458"><ix:nonFraction unitRef="shares" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:WeightedAverageNumberOfSharesOutstandingBasic" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTgtMy0xLTEtMA_a0649ff9-00da-4d93-9689-660b7cc486e2">47,833,607</ix:nonFraction></ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:WeightedAverageNumberOfSharesOutstandingBasic" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTgtNS0xLTEtMA_39bad7df-09e0-4caf-bc3e-f6a420fff539"><ix:nonFraction unitRef="shares" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yMi9mcmFnOjRlM2ZjMjc1M2U5MjRhMTRhZWFmZmZlOWE4OGRjNGRlL3RhYmxlOjA3M2EyZWU2NmNjZjRhYWU5YmQzMjc0YmQ4ODRjZGE5L3RhYmxlcmFuZ2U6MDczYTJlZTY2Y2NmNGFhZTliZDMyNzRiZDg4NGNkYTlfMTgtNS0xLTEtMA_82345e0d-4abc-423b-91cd-5dace67692e7">59,086,202</ix:nonFraction></ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000;border-top:3pt double #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The accompanying notes are an integral part of these condensed consolidated financial statements.</span></div><div style="margin-bottom:12pt"><span><br/></span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">5</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_25"></div><hr style="page-break-after:always"/><div style="min-height:36pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Condensed Consolidated Statements of Stockholders&#8217; Equity</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share data)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div><div style="margin-bottom:6pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:40.450%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:8.159%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.378%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:8.159%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.378%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:8.159%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.378%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:8.159%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.378%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:8.159%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.378%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:8.165%"></td><td style="width:0.1%"></td></tr><tr style="height:18pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">Common&#160;Stock</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">Additional <br/>Paid-in <br/>Capital</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">Accumulated <br/>Other Comprehensive<br/>Income (Loss)</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">Accumulated <br/>Deficit</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">Stockholders&#8217; <br/>Equity</span></td></tr><tr style="height:12pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:700;line-height:100%">Shares</span></td><td colspan="3" style="border-top:1pt solid 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2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New 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contextRef="i8239d5b5594f49c78424f1bdc9b62644_D20190101-20190331" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNC0zLTEtMS0w_8a2e9fa9-18ec-41e5-a7bc-c1b06c644707">2</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i8bb1bbb8be41430093c807e587be2e8b_D20190101-20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNC01LTEtMS0w_606361c3-7698-4964-8295-c7a7fc0341fe">92,160</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i91bd7b7043ae4943bf7a5ffe055932df_D20190101-20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNC0xMS0xLTEtMA_62268e75-15a6-4b6e-bb11-465a36995bba">92,162</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Stock-based compensation expense</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i8bb1bbb8be41430093c807e587be2e8b_D20190101-20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNS01LTEtMS0w_6f6cef6d-29e5-4063-a5c7-6c1f8b890896">1,164</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i91bd7b7043ae4943bf7a5ffe055932df_D20190101-20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNS0xMS0xLTEtMA_18c6d83b-d5ec-484c-a7e9-c2861af042e1">1,164</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Other comprehensive income</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i9f0d209f60c94186bbd5f236f3e4b09f_D20190101-20190331" decimals="-3" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNi03LTEtMS0w_68ce03b1-3411-4526-89e0-37539efd82ab">8</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 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style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i92c6982faacf48ffa82504edce933b27_I20190331" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfOC0zLTEtMS0w_38ff5e29-d9b1-4941-8f8a-b8c8e5b45762">5</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="iad4f0a0c6c9a4a0d871f8a67d6a2a7be_I20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfOC01LTEtMS0w_a6be02f4-d3d1-4451-902e-2aba38b991d2">266,332</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i38e064fa2e8241e7a4d63522bdc195d3_I20190331" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ie055fd0e2950455e98ab9260e64ca947_I20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfOC0xMS0xLTEtMA_da3708be-42a1-4a6d-9127-94562772d200">124,072</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Exercise of stock options</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i1b3b293c07694961a2efb2657cec51b0_D20190401-20190630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesStockOptionsExercised" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfOS0xLTEtMS0w_7900d54e-efc8-4c9f-abf8-1b4fed21d772">32,693</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i08a37be75c93481993a1f2c975d33625_D20190401-20190630" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfOS01LTEtMS0w_d99334a0-b3aa-4d6a-9995-139579fdd069">58</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i9614a2f4471247c7995195150f2d3536_D20190401-20190630" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" 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style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i9614a2f4471247c7995195150f2d3536_D20190401-20190630" decimals="-3" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTAtMTEtMS0xLTA_0d45e061-3061-428c-8795-e36c298446e4">283</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Stock-based compensation expense</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New 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style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i9614a2f4471247c7995195150f2d3536_D20190401-20190630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTEtMTEtMS0xLTA_11a5c8ea-a99f-40b9-8fe1-4f97af543ccd">1,161</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Other comprehensive income</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span 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style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i61e9b18d05a6401bb98e70909cc1c504_D20190401-20190630" decimals="-3" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTItNy0xLTEtMA_aba79be7-0604-4d62-b144-e0eb8fce6d3d">11</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 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style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i9278d87ceda2479aa49a1fb1357916bc_D20190401-20190630" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTMtOS0xLTEtMA_9c2cabaf-b648-4ca0-b65a-f06427dc13e4">17,071</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i9614a2f4471247c7995195150f2d3536_D20190401-20190630" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ib4bb28a5fe4842ba915cf75eb0a11fe0_I20190630" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTQtNy0xLTEtMA_97c7c709-3693-4b83-963e-2a1c39f40ae3">11</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i7cc88053299c4b5d95217135dbd1e6ce_I20190630" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTQtOS0xLTEtMA_c25d2bbd-83b0-443d-8926-161dff68acef">159,336</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i3f9ff83e4da14ebdaa5f5fc31e7274a4_I20190630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTUtNS0xLTEtMA_16970097-2889-454c-a276-2c66f7d7a95e">21</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="mrsn:StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTUtMTEtMS0xLTA_9a2e408f-0b41-400b-8f29-d6d90511f693">21</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Stock-based compensation expense</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i431514045cae4ad38f492d256f0404da_D20190701-20190930" 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style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTYtMTEtMS0xLTA_b9cc99c8-023c-467c-a993-d4b8b76adc76">1,285</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Other comprehensive income</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="iba3574e0f1154c05863af391982338e6_D20190701-20190930" decimals="-3" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTctNy0xLTEtMA_0e219e1a-567a-4793-802f-e0e2c67148c1">17</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTctMTEtMS0xLTA_a4a58be0-7000-4aba-8497-3151d88982ef">17</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Net loss</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i8c017164a949463ab9bb01aa4b732bd2_D20190701-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTgtOS0xLTEtMA_05965f64-c6ef-4b14-bbbe-d2c2d6eebb82">16,792</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTgtMTEtMS0xLTA_ed1174e0-6bc1-4230-be71-498f8f130d55">16,792</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Balance at September 30, 2019</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i7196ab3884224da581a2177db6d2e142_I20190930" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTktMy0xLTEtMA_d82bddd4-04e2-4cb8-8a74-c0482bc7253d">5</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i1d178a5542a94734857f4a9f9ee83904_I20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTktNS0xLTEtMA_8f43d19d-82d9-48c2-a997-33dec00031d0">269,140</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="if025665dee5844808ec41b639a64d0a4_I20190930" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTktNy0xLTEtMA_0bb448e6-87e1-4f87-8d34-ee890e3e0a6b">28</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i5befde5b05fc46dcae56f60bde86ad17_I20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTktOS0xLTEtMA_9f622c79-c012-4664-85ac-cfb22bc55554">176,128</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ic48446a1712f42aab763e9766cd66f76_I20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMTktMTEtMS0xLTA_fe935c8a-d2c6-4ed2-99dd-c03a88dd712c">93,045</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:top"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Retirement of common stock in exchange for common stock warrant</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i966575cf95534e50a9c96259087afaf4_D20191001-20191231" decimals="-3" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" scale="3" 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style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i966575cf95534e50a9c96259087afaf4_D20191001-20191231" decimals="-3" name="mrsn:StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised" scale="3" 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i966575cf95534e50a9c96259087afaf4_D20191001-20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMjQtMTEtMS0xLTA_868c277f-5e0f-41bf-8a1f-0443a03712e4">1,262</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Other comprehensive loss</span></td><td 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i281ceacc23bb4cea85bff3bae2476d1a_D20191001-20191231" decimals="-3" sign="-" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMjUtNy0xLTEtMA_97ded2e0-f691-4904-956e-9a6e060948cb">3</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i966575cf95534e50a9c96259087afaf4_D20191001-20191231" decimals="-3" sign="-" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMjUtMTEtMS0xLTA_3cca4417-f032-4b7a-916c-53df1f61cf44">3</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:top"><span 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style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i13f1ebf220a04c41ab643d198a541a2e_I20191231" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" 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style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i8b267bc33d574b148631ed66fe169e53_I20191231" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" 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style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i32b55d2ee1884e8dbc7c46cb9f8daa87_D20200101-20200331" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMjktNS0xLTEtMA_db25a4c9-8c2f-400d-9640-412902f9f959">119</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMjktMTEtMS0xLTA_93e16730-d7a7-423a-9cb6-98c561d1c76d">119</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Stock-based compensation expense</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i32b55d2ee1884e8dbc7c46cb9f8daa87_D20200101-20200331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzAtNS0xLTEtMA_6c402b5a-5727-4724-870c-310454f6d272">1,609</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzAtMTEtMS0xLTA_9560b1ea-1feb-43eb-9a91-8ebcabe613b7">1,609</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Other comprehensive loss</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i26628584a365486c9a348345c9047217_D20200101-20200331" decimals="-3" sign="-" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzEtNy0xLTEtMA_64ba4a0a-d7a9-4160-b912-81d37ba1f297">29</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331" decimals="-3" sign="-" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzEtMTEtMS0xLTA_50102237-ba46-4df8-8192-eba09cdf2ac5">29</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Net loss</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i8d14f3358fd94d7ea83d65b58d165758_D20200101-20200331" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzItOS0xLTEtMA_dd0260fb-85f2-4a4f-aef7-dbf3caa25b88">16,926</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzItMTEtMS0xLTA_928801df-4c6d-41d5-bf4c-8a0eb30c3a8c">16,926</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Balance at March 31, 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style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id9a118b70aa54023a86d6018f98ca0bc_I20200331" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzMtMy0xLTEtMA_a4c71db6-22e0-4d3f-9997-545ea8e70f18">5</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ic2184877ef6b40acbbd95d0993fba8cd_I20200331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzMtNS0xLTEtMA_3eade532-5c16-43ed-8df6-f6c08da5716a">272,390</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i2487adba71854d158990c01ac7f8cdc5_I20200331" decimals="-3" sign="-" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzMtNy0xLTEtMA_2403efe3-9fcc-4f96-8d54-f8d37c80ab45">4</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i647f988e5c494ff1a928fb60a0a071c8_I20200331" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzMtOS0xLTEtMA_5f43afb1-bff6-440c-9340-46276c2f9c68">209,300</ix:nonFraction>)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i952bc03d36944238b444b398dfbc01d8_I20200331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzMtMTEtMS0xLTA_988418bb-422f-4925-a675-cd81647b9aa5">63,091</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Issuance of common stock from at-the-market transactions, net of issuance costs of $<ix:nonFraction unitRef="usd" contextRef="ia06ccf041d454630aa9d31a21183e91b_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="mrsn:StockIssuanceDiscountsAndCommissionsOnTransaction" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzQtMC0xLTEtMC90ZXh0cmVnaW9uOjYzMDNkNzg0ZTczYjRhOWRiMDE5Nzg1YTJmNDA5OWU1Xzg3_719ace12-314e-4956-ad28-7a9741147bb4">2,176</ix:nonFraction></span></div></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i8987ac1fb8a745b289822f555f3b8f1b_D20200401-20200630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzQtMS0xLTEtMA_7711e4b1-4505-4c8c-8fc7-05cec8c1c0e2">10,900,599</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i8987ac1fb8a745b289822f555f3b8f1b_D20200401-20200630" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzQtMy0xLTEtMA_0bfd6ed2-4844-4da4-aa2a-cbd37615e115">1</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="if2fb9b82d5784cfc9bcf9cce9f7c0e87_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzQtNS0xLTEtMA_a6fbbd89-71f0-405d-bd71-e5a193a6bf2e">62,976</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ia06ccf041d454630aa9d31a21183e91b_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzQtMTEtMS0xLTA_fb40ba0d-fd30-4b95-b4f3-b15a074d2b91">62,977</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:6pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Issuance of common stock under public offering, net of issuance costs of $<ix:nonFraction unitRef="usd" contextRef="i6885c1cb19614100bdf2617799fa13a5_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="mrsn:StockIssuanceDiscountsAndCommissionsOnTransaction" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzUtMC0xLTEtMC90ZXh0cmVnaW9uOjM0Mjk0ZTY5NjViZjQzZWFiYzViY2E1N2U1MjlmNTJmXzc3_79d87a29-488f-4ad2-b351-a43d11a7b66d">10,809</ix:nonFraction></span></div></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="ide448a02c0d0442e86a5c10d8ed1b804_D20200401-20200630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzUtMS0xLTEtMA_c7538e50-a477-4664-8192-c3b7fdc3ad82">9,200,000</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ide448a02c0d0442e86a5c10d8ed1b804_D20200401-20200630" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzUtMy0xLTEtMA_1a9f79c7-61d0-4eb8-bf56-ec7d9c6ebd0b">1</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ie2b377f74be54438a6670ac01d14c379_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzUtNS0xLTEtMA_562d3714-fb25-4dc2-b9fe-eb5d33d984b4">163,990</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i6885c1cb19614100bdf2617799fa13a5_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueNewIssues" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzUtMTEtMS0xLTA_66074013-5f77-482f-8f7f-338d4b401179">163,991</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Purchase of common stock under ESPP</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="ic92d724d8ba844c68f57d652870a7201_D20200401-20200630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzYtMS0xLTEtMA_f03949e2-c1d8-4973-88b6-4206d76d9a78">68,419</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i3f273d76795c4c5182dc370c21e64670_D20200401-20200630" decimals="-3" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzYtNS0xLTEtMA_cf195a9f-31f3-465f-9a19-200b891b40c9">333</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i900dc81fd54948df91c7a493de4278f6_D20200401-20200630" decimals="-3" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzYtMTEtMS0xLTA_0b743244-25af-410a-a0f6-b4489788b23e">333</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Exercise of stock options</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction 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style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i900dc81fd54948df91c7a493de4278f6_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzctMTEtMS0xLTA_8d5f47b3-d559-4b42-bd3e-b390cf0fd2cc">1,296</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Stock-based compensation expense</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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contextRef="i3f273d76795c4c5182dc370c21e64670_D20200401-20200630" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzgtNS0xLTEtMA_5973da20-e5cd-4706-ae81-46245b903212">1,656</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzktNy0xLTEtMA_12555654-78dd-4857-b582-7dedf47f3f61">6</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i900dc81fd54948df91c7a493de4278f6_D20200401-20200630" decimals="-3" name="us-gaap:OtherComprehensiveIncomeLossNetOfTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfMzktMTEtMS0xLTA_82b48702-e493-475c-8fbb-d7ef5586c0c4">6</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Net loss</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i02ac04061d4945329c18cfee25ab2a42_I20200630" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ib5185b37f4394db9bb778afaee6769a5_I20200630" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNDEtNy0xLTEtMA_0d61fd44-368b-46b2-bb5a-0df45f413fc2">2</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" 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style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i65608e1df80a46328af90a9ecf5f3119_D20200701-20200930" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNDItNS0xLTEtODIx_2f22ea0d-d706-47ec-8607-b8cff18e0529">317</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" name="us-gaap:StockIssuedDuringPeriodValueStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yNS9mcmFnOmNhNWQ2NTgxNWYxMDRjZjVhMWU0YWQxYzg5ZGE0MmYzL3RhYmxlOmE4MjBhYzUzZTY1MTRjNmNhMDU1NDE3N2E5YmIxNDEwL3RhYmxlcmFuZ2U6YTgyMGFjNTNlNjUxNGM2Y2EwNTU0MTc3YTliYjE0MTBfNDMtMTEtMS0xLTMzOA_1c779185-e276-4bb2-95e5-07284edf3ae1">317</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">Stock-based compensation expense</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" 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Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" 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0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2bece65caa624c11b3dc1e579d2417c8_I20200930" decimals="-3" name="us-gaap:StockholdersEquity" scale="3" 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style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:7pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:StockholdersEquity" scale="3" 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style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">6</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_28"></div><hr style="page-break-after:always"/><div style="min-height:36pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Condensed Consolidated Statements of Cash Flows</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Cash flows from operating activities</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net loss</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:ProfitLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMy0zLTEtMS0w_48f6ef95-f646-4b1c-bc83-4b9e9ca71582">11,962</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Adjustments to reconcile net loss to net cash used in operating activities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Depreciation</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" name="us-gaap:OtherNoncashIncomeExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTAtMy0xLTEtMA_81735120-8b08-40e0-90ec-9f49ae7c1443">65</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 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1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTMtMy0xLTEtMA_9749e28e-34f7-402d-a874-565f88276c46">1,318</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 18pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other assets</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:IncreaseDecreaseInOtherOperatingAssets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTQtMS0xLTEtMA_e3286319-3aa4-4b06-9be0-fab559c36f00">700</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:zerodash" name="us-gaap:IncreaseDecreaseInOtherOperatingAssets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTQtMy0xLTEtMA_fc1b1205-d544-45c6-9644-7d0130358bf1">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 18pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accounts payable</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:IncreaseDecreaseInAccountsPayable" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTUtMS0xLTEtMA_d4d02fda-28b3-409b-b3a8-1a521d6c2acd">2,766</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:IncreaseDecreaseInAccountsPayable" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTUtMy0xLTEtMA_39413c1b-d24c-4f81-8a92-7b0fecee50e5">3,102</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 18pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued expenses</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:IncreaseDecreaseInAccruedLiabilities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTYtMS0xLTEtMA_b0584c73-515c-4850-9e23-3a002e84f09f">2,367</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:IncreaseDecreaseInAccruedLiabilities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTYtMy0xLTEtMA_79e99642-7255-46e8-890f-8dd5c5f97660">4,518</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 18pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Operating lease assets</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 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1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:IncreaseDecreaseInOperatingLeaseAssets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTctMy0xLTEtMA_53c68de5-e660-4d5d-ae9c-6ce72becaee6">1,290</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 18pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Operating lease liabilities</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="mrsn:IncreaseDecreaseInOperatingLeaseLiabilities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTgtMS0xLTEtMA_1584d939-feff-48e4-a0fc-7a3bc59c2f42">990</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:IncreaseDecreaseInOperatingLeaseLiabilities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTgtMy0xLTEtMA_c01a91ce-672a-4b05-bc94-42e4cdaff78e">1,356</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 18pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" name="us-gaap:IncreaseDecreaseInContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTktMS0xLTEtMA_71572f7c-144a-456f-bff6-3b29127ff2eb">817</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:IncreaseDecreaseInContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMTktMy0xLTEtMA_f7fdcce4-4048-4e4a-8744-437bd490a8bf">41,550</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net cash used in operating activities</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetCashProvidedByUsedInOperatingActivities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjAtMS0xLTEtMA_02372fb5-e6d1-45c2-aba9-a31f79550b1e">57,377</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetCashProvidedByUsedInOperatingActivities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjAtMy0xLTEtMA_716cafae-f9af-47b3-acea-cd3ace50a9e2">55,168</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr style="height:12pt"><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Cash flows from investing activities</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Maturities of marketable 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style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjMtMy0xLTEtMA_4e6fe3dd-6605-4a62-8f44-f3f8db2a88ad">10,500</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Purchase of marketable securities</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:zerodash" name="us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjQtMS0xLTEtMA_ee196b11-79d8-47eb-b559-fa4aad93cde0">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjQtMy0xLTEtMA_3d9da6f5-95d2-42a3-815b-d71f9fff1c7f">53,688</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Purchase of property and equipment</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:PaymentsToAcquirePropertyPlantAndEquipment" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjUtMS0xLTEtMA_0e6dd1dd-7d66-4e10-a0b3-0756aedd51ab">285</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:PaymentsToAcquirePropertyPlantAndEquipment" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjUtMy0xLTEtMA_ed9bff51-8cfe-441a-8a90-aace341a6703">605</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net cash provided by (used in) investing activities</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:NetCashProvidedByUsedInInvestingActivities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjYtMS0xLTEtMA_0ddc83cf-f371-4d18-ada2-ea54d3e72766">37,215</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetCashProvidedByUsedInInvestingActivities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjYtMy0xLTEtMA_6f014295-0e70-4c50-8f1d-47ed9510bbb8">43,793</ix:nonFraction>)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr style="height:12pt"><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Cash flows from financing activities</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net proceeds from public offering of common stock</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ifa9047c5f0c64fe2a39f8a7229cac5d0_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ProceedsFromIssuanceOfCommonStock" scale="3" 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMjktMy0xLTEtMA_fb1f8f2b-c6c4-4354-9b50-0418d8b73aa0">92,162</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net proceeds from the at-the-market (ATM) facility</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="if0f036969b2b46d486823b74dd93e058_D20190101-20190930" decimals="-3" format="ixt:zerodash" name="us-gaap:ProceedsFromIssuanceOfCommonStock" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzAtMy0xLTEtMA_0290eec6-1f3d-4fb0-b2a8-c219c00b88eb">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Proceeds from exercise of stock options</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ProceedsFromStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzEtMS0xLTEtMA_12f8e4f8-b937-479d-bc28-b7c3defa1b0c">1,732</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:ProceedsFromStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzEtMy0xLTEtMA_f3c462b6-cc0e-4b2a-86a3-4009b78dd204">121</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Proceeds from purchases of common stock under ESPP</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzItMS0xLTEtMA_90406e48-a628-4be7-8b77-45fb2f1c7c20">333</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzItMy0xLTEtMA_1902bdf7-2780-48a3-bcad-8f9620eed338">283</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Proceeds from issuance of debt, net of issuance costs</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" name="mrsn:ProceedsFromDebtNetIssuanceCosts" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzMtMS0xLTEtMA_9a55bb02-d27f-4fa0-9e24-0821b85e4aa2">197</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Payments under capital lease obligations</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:FinanceLeasePrincipalPayments" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzQtMS0xLTEtMA_ecbe6a4b-4f4d-460f-8cb4-1e4670ef28e4">87</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:FinanceLeasePrincipalPayments" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzQtMy0xLTEtMA_56cf3ced-8d91-42cf-bd85-c9237ad2c189">58</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net cash provided by financing activities</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:NetCashProvidedByUsedInFinancingActivities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzUtMS0xLTEtMA_533b6595-c9ac-407b-8547-52224acd752e">228,747</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:NetCashProvidedByUsedInFinancingActivities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzUtMy0xLTEtMA_cf4ffcd7-1b2b-450f-b955-24a84b46d5bc">97,473</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr style="height:12pt"><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Increase (decrease) in cash, cash equivalents and restricted cash</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzctMS0xLTEtMA_3de1beb4-ffc5-4b16-b620-4483631cabc7">208,585</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzctMy0xLTEtMA_e4ab8227-5172-4fbe-b7b4-5bc0d81337d2">1,488</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash, cash equivalents and restricted cash, beginning of period</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash, cash equivalents and restricted cash, end of period</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzktMS0xLTEtMA_d0c71fed-a60b-4bc1-95bf-fc20486be707">271,257</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ic48446a1712f42aab763e9766cd66f76_I20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfMzktMy0xLTEtMA_a0ab1742-2b10-4e5d-9da0-ea3787066fb5">58,517</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr style="height:12pt"><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:3pt double #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:3pt double #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Supplemental disclosures of non-cash activities:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Debt financing costs in accrued expenses</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:zerodash" name="us-gaap:DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfNDMtMS0xLTEtMA_a3982fe1-b3a5-45fb-acc6-2e1c903d2d73">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfNDMtMy0xLTEtMA_6566aedd-1651-49fd-834f-b9b25ea7334c">180</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash paid for interest</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:InterestPaidNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfNDUtMS0xLTEtMA_2824d8ae-00d8-41ba-ae5a-1171d38aa784">173</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction 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1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfNDYtMS0xLTEtMA_1804e92c-ac5d-42ad-9126-6b6ffe04dbd8">9,980</ix:nonFraction>&#160;</span></td><td 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:zerodash" name="us-gaap:RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfNDctMS0xLTEtMA_d71e27a4-5fd9-4968-a933-31c3e58ec5ff">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8yOC9mcmFnOjM2MDQ0OTFkZTBlZDRiOTU5MGI2MzE1NDZkMzU5Y2NlL3RhYmxlOmQ4MDM1NGQxMzcxNzQ1ODc5MmNkYTIyMmVkZjk2ZjdkL3RhYmxlcmFuZ2U6ZDgwMzU0ZDEzNzE3NDU4NzkyY2RhMjIyZWRmOTZmN2RfNDctMy0xLTEtMA_34119bdb-924f-4a22-b2d2-b710ed1f9f4a">429</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr></table></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The accompanying notes are an integral part of these condensed consolidated financial statements.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">7</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_31"></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><div style="text-align:center"><span><br/></span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_34"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">1.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:BusinessDescriptionAndBasisOfPresentationTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfNjAwNw_108015d0-40f8-4836-91a8-2cbc8ba7c21c" continuedAt="i98b0a90c09a244a588a15243fb394ef7" escape="true">Nature of business and basis of presentation</ix:nonNumeric></span></div><ix:continuation id="i98b0a90c09a244a588a15243fb394ef7" continuedAt="i2634a1d6eb904da4a46e1c3cef68f5ed"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Mersana Therapeutics, Inc. is a clinical stage biopharmaceutical company focused on developing antibody drug conjugates (ADCs) that offer a clinically meaningful benefit for cancer patients with significant unmet need. The Company has leveraged 20&#160;years of industry learning in the ADC field to develop proprietary and differentiated technology platforms that enable it to design ADCs to have improved efficacy, safety and tolerability relative to existing ADC therapies. The Company&#8217;s innovative platforms, which include Dolaflexin and Dolasynthen, each delivering its DolaLock payload, as well as Immunosynthen, delivering a novel stimulator of interferon genes (STING) agonist, provide an efficient product engine that has enabled a robust discovery pipeline for the Company and its partners. The Company&#8217;s product candidates include XMT-1536 and XMT-1592. The Company's early stage programs include a potentially first-in-class B7-H4-targeted DolaLock ADC as well as candidates leveraging the Immunosynthen platform. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">XMT-1536, an ADC utilizing the Company&#8217;s Dolaflexin platform and targeting NaPi2b, an antigen broadly expressed in ovarian cancer and non-small cell lung cancer (NSCLC) adenocarcinoma, is currently in the expansion portion of a Phase 1 study in patients with ovarian cancer and NSCLC adenocarcinoma. XMT-1592 uses one of the Company&#8217;s new platforms, Dolasynthen, and also targets NaPi2b. The Company filed an Investigational New Drug (IND) application in the first quarter of 2020 and initiated the Phase 1 dose escalation study of XMT-1592 in the second quarter of 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company has incurred cumulative net losses since inception. For the nine months ended September&#160;30, 2020, the net loss was $<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMTc1Ng_cd73174a-b504-480f-923f-ba050cbf6741">59,203</ix:nonFraction>, compared to net loss of $<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:NetIncomeLoss" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMTc4Ng_f0fee407-9ff0-4f06-b08c-d2ab3380d908">11,962</ix:nonFraction> in the nine months ended September&#160;30, 2019. The difference year over year is primarily attributable to $<ix:nonFraction unitRef="usd" contextRef="i661bd2f150a14e4187f1345b75ecb953_D20190101-20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiabilityRevenueRecognized" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMTg3NQ_a2d2b2d8-b313-46fa-ac17-633deffb3979">39,965</ix:nonFraction> in deferred revenue that was recognized in the first quarter of 2019 as a result of the discontinuation of the partnership with Takeda in that quarter. The Company expects to continue to incur operating losses for at least the next several years. As of September&#160;30, 2020, the Company had an accumulated deficit of $<ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" sign="-" format="ixt:numdotdecimal" name="us-gaap:RetainedEarningsAccumulatedDeficit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMjE5MA_f63c4c7d-431f-49d7-a795-fd91e4f40c6a">251,575</ix:nonFraction>. The future success of the Company is dependent on, among other factors, its ability to identify and develop its product candidates and ultimately upon its ability to attain profitable operations. The Company has devoted substantially all of its financial resources and efforts to research and development and general and administrative expense to support such research and development. Net losses and negative operating cash flows have had, and will continue to have, an adverse effect on the Company&#8217;s stockholders' equity and working&#160;capital.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In April 2020, the Company sold <ix:nonFraction unitRef="shares" contextRef="ie0c01d25fe5c457bac585a0199b91d06_D20200401-20200430" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMjc3MQ_c4975181-5758-471e-b8b4-1f3ace9fd920">10,900,599</ix:nonFraction> shares of common stock and received net proceeds of $<ix:nonFraction unitRef="usd" contextRef="ie0c01d25fe5c457bac585a0199b91d06_D20200401-20200430" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMjgyNg_7f80437a-4508-45ea-a800-f56f297fc3b1">62,976</ix:nonFraction>. In addition, in June 2020, the Company sold <ix:nonFraction unitRef="shares" contextRef="i14c2e05a25d8436dabfbefc31e1a1f13_D20200601-20200630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMjg3NA_f9c94c23-ef50-4f70-a92b-37a5948a02c3">9,200,000</ix:nonFraction> shares of common stock and received net proceeds of $<ix:nonFraction unitRef="usd" contextRef="i14c2e05a25d8436dabfbefc31e1a1f13_D20200601-20200630" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl8zNC9mcmFnOjY4MWMyNzFjOWY0NTQzYzZhYjg2NDQ1ZDRmMzRhNzgxL3RleHRyZWdpb246NjgxYzI3MWM5ZjQ1NDNjNmFiODY0NDVkNGYzNGE3ODFfMjkyOQ_bbe65470-f56e-4be4-81d3-1986eacea10e">163,991</ix:nonFraction>. The Company believes that its currently available funds will be sufficient to fund the Company&#8217;s operations through at least the next twelve months from the issuance of this Quarterly Report on Form 10-Q. Management&#8217;s belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management&#8217;s estimates, the Company may need to seek additional funding.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, the need for additional capital, risks of failure of preclinical and clinical studies, the need to obtain marketing approval and reimbursement for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development of technological innovations by competitors, reliance on third party manufacturers and the ability to transition from pilot-scale production to large-scale manufacturing of products.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company&#8217;s unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S.&#160;GAAP) and the rules and regulations of the Securities and Exchange Commission (SEC). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards </span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">8</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i2634a1d6eb904da4a46e1c3cef68f5ed"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Updates (ASU) of the Financial Accounting Standards Board (FASB). All dollar amounts, except per share data in the text and tables herein, are stated in thousands unless otherwise indicated. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December&#160;31, 2019 and the notes thereto, included in the Company&#8217;s Annual Report on Form 10-K for the year ended December&#160;31, 2019 filed with the SEC on February 28, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements. In the opinion of the Company&#8217;s management, the accompanying unaudited condensed consolidated financial statements contain all adjustments that are necessary to present fairly the Company&#8217;s financial position as of September&#160;30, 2020, the results of its operations for the three and nine months ended September&#160;30, 2020 and 2019, a statement of stockholders&#8217; equity for the three and nine months ended September&#160;30, 2020 and 2019 and cash flows for the nine months ended September&#160;30, 2020 and 2019. Such adjustments are of a normal and recurring nature. The results for the three and nine months ended September&#160;30, 2020 are not necessarily indicative of the results for the year ending December&#160;31, 2020, or for any future period.</span></div></ix:continuation><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_40"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">2.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:SignificantAccountingPoliciesTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEyNw_be9fad9c-a990-4123-8c81-3503de3688ce" continuedAt="i5c1d6404acb141578de34cb89dd9b791" escape="true">Summary of Significant Accounting Policies</ix:nonNumeric></span></div><ix:continuation id="i5c1d6404acb141578de34cb89dd9b791" continuedAt="i0bb12e57a2654f2db784cb41882bfebf"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ConsolidationPolicyTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEyOA_529a1ac3-5feb-490e-ab57-9d210ed7791a" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Principles of Consolidation</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The accompanying unaudited condensed consolidated financial statements include those of the Company and its wholly owned subsidiary, Mersana Securities Corp. All intercompany balances and transactions have been eliminated.</span></div></ix:nonNumeric><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:UseOfEstimates" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEyNA_da535198-3a63-41d0-ad8f-cd59b68b2b88" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of the Company&#8217;s unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company&#8217;s management evaluates its estimates which include, but are not limited to, management&#8217;s judgments with respect to the identification of performance obligations and standalone selling prices of those performance obligations within its revenue arrangements, accrued expenses, valuation of stock-based awards and income taxes. Actual results could differ from those estimates.</span></div></ix:nonNumeric><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:SegmentReportingPolicyPolicyTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTExNg_fde7f9ba-f8b8-4eda-8938-3aae98ca303c" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Segment Information</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker, or decision making group, in deciding how to allocate resources and assess performance. The Company views its operations and manages its business as a single operating segment, which is the business of discovering and developing ADCs.</span></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Summary of Accounting Policies</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and nine months ended September&#160;30, 2020 are consistent with those discussed in Note 2 to the consolidated financial statements in the Company&#8217;s 2019 Annual Report on Form 10-K, except as otherwise noted below in "Recently Issued Accounting Pronouncements."</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">9</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i0bb12e57a2654f2db784cb41882bfebf" continuedAt="ie3ba7f263e654dab950abf865420c9f6"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:FairValueMeasurementPolicyPolicyTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEyNQ_8749bc18-4d47-463d-8479-368098f50219" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Fair Value Measurements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. 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style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash and cash equivalents</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashAndCashEquivalentsAtCarryingValue" scale="3" 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashAndCashEquivalentsAtCarryingValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfMi0zLTEtMS0w_d4dcf9ce-6cf2-4abf-b073-657652b09c03">270,936</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i741a90802bca471c9476b10ae9bdc2e8_I20181231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashAndCashEquivalentsAtCarryingValue" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfMi01LTEtMS0w_0b784901-b891-431b-ad7a-58dbeb932ec9">59,634</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfMi03LTEtMS0w_9a8c0290-375d-4fee-bf2a-cc9769664211">58,196</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted cash included in other assets, noncurrent</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i741a90802bca471c9476b10ae9bdc2e8_I20181231" decimals="-3" name="us-gaap:RestrictedCashNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfMy01LTEtMS0w_57886498-837b-4fb8-abc7-d8fcb78b6715">371</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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flows</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfNC0xLTEtMS0w_3cead958-3ce0-4b74-bd2d-049e68e54088">62,672</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfNC0zLTEtMS0w_1b3cc910-bfff-46b8-b9eb-3cd273bee289">271,257</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i741a90802bca471c9476b10ae9bdc2e8_I20181231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RhYmxlOmZiMmZmMDE5NTE1MTQzNjJiNzdiYmMwNDMwZjUxZTk4L3RhYmxlcmFuZ2U6ZmIyZmYwMTk1MTUxNDM2MmI3N2JiYzA0MzBmNTFlOThfNC01LTEtMS0w_5837b6df-dd1a-4dfe-b197-a7120a0a5a27">60,005</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid 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0;text-align:right;vertical-align:bottom"></td></tr></table></ix:nonNumeric></ix:nonNumeric></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:MarketableSecuritiesPolicy" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEyMg_dd206906-3b3d-4cf8-8e9a-d216446812d6" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Marketable Securities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Short-term marketable securities consist of investments in debt securities with maturities greater than three months and less than one year from the balance sheet date. The Company classifies all of its marketable securities as available-for-sale. Accordingly, these investments are recorded at fair value. Amortization and accretion of discounts and premiums are recorded as interest income within other income. Prior to the adoption of ASU 2016-13,</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"> Financial Instruments - Credit Losses</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, unrealized gains and losses on available-for-sale securities are included in other accumulated comprehensive income (loss) as a component of stockholders&#8217; equity until realized. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other income (expense), net, based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers various factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. Fair value is determined based on quoted market prices.</span></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDM5ODA0NjUyMDI0MQ_1ba23683-f895-48dd-b48b-585f8c5902d9" continuedAt="i4eddd9c4d93f4628b1fbf0c0ee235e8d" escape="true">Other Assets</ix:nonNumeric></span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:continuation id="i4eddd9c4d93f4628b1fbf0c0ee235e8d">The Company recorded other assets of $<ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OtherAssetsNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDYxOQ_85e875af-9e73-44f9-af6a-4e55011c097e">2,153</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:OtherAssetsNoncurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDYyNg_15e95941-2abd-401a-a778-b634a4082de7">1,453</ix:nonFraction> as of September&#160;30, 2020 and December&#160;31, 2019, respectively, comprised of $<ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:RetainageDeposit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDY3Mw_084cf41d-8e43-45e8-ae99-00125a7db853">1,832</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:RetainageDeposit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDY4MA_db52f8b3-b20c-4c6e-9e23-521950f3b1e2">1,132</ix:nonFraction>, respectively, held by a service provider, and restricted cash of $<ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:SecurityDeposit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDc0OQ_e4c1b660-2734-4f36-a6f2-c7aa2e95fb68"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="us-gaap:SecurityDeposit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfNDc0OQ_f9f1a975-c187-408f-8e31-aea5036b3386">321</ix:nonFraction></ix:nonFraction> at the end of each period held as security deposits for a standby letter of credit related to a facility lease.</ix:continuation> </span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">10</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="ie3ba7f263e654dab950abf865420c9f6"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:EarningsPerSharePolicyTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTExOA_37d7d088-9c3b-4ecb-865c-4baad0d8dce8" continuedAt="i52243252b1d44e4c93030ddc17759f25" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Net Loss per Share</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without further consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury stock and if-converted methods.</span></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:continuation id="i52243252b1d44e4c93030ddc17759f25">For purposes of the diluted net loss per share calculation, stock options, unvested restricted stock units (RSUs), warrants to purchase common stock and options to purchase common stock are considered to be potentially dilutive securities, but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented.</ix:continuation> </span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTExOQ_3056533c-38d9-4aba-bc99-5d33629c25c9" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table sets forth the outstanding potentially dilutive securities that have been excluded from the calculation of diluted net loss per share for the three and nine months ended September&#160;30, 2020 and 2019, because to include them would be anti-dilutive (in common stock equivalent shares):</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"> </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:49.541%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:23.258%"></td><td style="width:0.1%"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td><td style="width:0.1%"></td><td style="width:0.441%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:23.260%"></td><td style="width:0.1%"></td><td colspan="3" style="display:none"></td><td colspan="3" style="display:none"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three and Nine Months Ended<br/>September 30, 2020</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three and Nine Months Ended<br/>September 30, 2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i98180811ba9d4037810b2ae10eb18d14_D20200701-20200930" decimals="INF" format="ixt:numdotdecimal" 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEzMA_f15403c1-a369-4400-ad42-c7c044c6c8c8" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Recently Issued Accounting Pronouncements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In November 2018, the FASB issued ASU No. 2018-18, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. The main provisions of ASU 2018-18 include: (i) clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue when the collaborative arrangement participant is a customer in the context of a unit of account and (ii) precluding the presentation of transactions with collaborative arrangement participants that are not directly related to sales to third parties together with revenue. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The guidance per ASU 2018-18 is to be adopted retrospectively to the date of initial application of Topic 606. The Company adopted the new standard effective January 1, 2020. The adoption of this standard did not have a material impact on the Company&#8217;s consolidated financial statements and related disclosures.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2016, the FASB issued ASU 2016-13, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, which requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. Historically, U.S. GAAP delayed recognition of the full amount of credit losses until the loss was probable of occurring. Under this ASU, the income statement will reflect an entity&#8217;s current estimate of all expected credit losses. The measurement of expected credit losses will be based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down of the security. This ASU is effective for annual periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The Company adopted the new standard effective January 1, 2020 using the modified retrospective method. The adoption of this standard did not have a material impact on the Company&#8217;s consolidated financial statements and related disclosures.</span></div></ix:nonNumeric></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">11</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_46"></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">3.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:CollaborativeArrangementDisclosureTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfOTMxMw_8bef03cd-e922-4e19-8c1e-8a1dbeb17394" continuedAt="i9db6602acf114597855273fde2473541" escape="true">Collaboration agreements</ix:nonNumeric></span></div><ix:continuation id="i9db6602acf114597855273fde2473541" continuedAt="i6aa3f564799840c3851a665b2db62c37"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Merck KGaA</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2014, the Company entered into a Collaboration and Commercial License Agreement with Merck KGaA (the Merck KGaA Agreement). Upon the execution of the agreement, Merck KGaA paid the Company a nonrefundable technology access fee of $<ix:nonFraction unitRef="usd" contextRef="ie8d1aab2f2f4458bb13b81a9e0e27cc7_D20140601-20140630" decimals="-3" format="ixt:numdotdecimal" name="mrsn:CollaborativeArrangementsUpfrontPayment" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMjgy_00190294-d5a3-4d6d-9811-100210694de8">12,000</ix:nonFraction> for the right to develop ADCs directed to <ix:nonFraction unitRef="target" contextRef="i261a9dc5ded54b49a0126b5207e01fbb_I20140630" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:CollaborativeArrangementsExclusiveTargetsNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzI3_c98825f2-04ce-4b65-9271-6a4e7d201e7d">six</ix:nonFraction> exclusive targets over a specified period of time. <ix:nonFraction unitRef="usd" contextRef="i261a9dc5ded54b49a0126b5207e01fbb_I20140630" decimals="-3" format="ixt-sec:numwordsen" name="mrsn:CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzgx_9e4f098a-6610-4426-a4d7-592ee6d2d407">No</ix:nonFraction> additional fees are due when a target is designated and the commercial license to the target is granted. Merck KGaA will be responsible for the product development and marketing of any products resulting from this collaboration.&#160;All <ix:nonFraction unitRef="target" contextRef="i7b79e5c7375d45daa227309f15ced2f6_I20171231" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:CollaborationArrangementsTargetsDesignatedNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNjE3_a5b2c1c4-e1b0-461f-8d8d-125e8d2608fc">six</ix:nonFraction> targets were designated prior to 2018. The Company is eligible to receive milestones under the Merck KGaA Agreement. The next potential milestone payment is a development milestone of $<ix:nonFraction unitRef="usd" contextRef="icd7ccd1339114bfaaaa1f1e9ebd9c9f9_I20200930" decimals="-3" name="mrsn:CollaborationArrangementsDevelopmentMilestonesPaymentReceivableNextMilestone" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfODA0_cb3d1a9c-04a8-4571-ae6a-a54759b31685">500</ix:nonFraction> on Merck KGaA&#8217;s designation of a preclinical development candidate for a target. Revenue for the milestone is fully constrained until it is certain the milestone would be achieved.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Under the terms of the Merck KGaA Agreement, the Company and Merck KGaA develop research plans to evaluate Merck KGaA's antibodies as ADCs incorporating the Company's technology. The Company receives reimbursement for its efforts under the research plans. The goal of the research plans is to provide Merck KGaA with sufficient information to formally nominate a development candidate and begin IND-enabling studies or cease development on the designated target.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In May 2018, the Company entered into a Supply Agreement with Merck KGaA (the Merck KGaA Supply Agreement). Under the terms of the Merck KGaA Supply Agreement, the Company will provide Merck KGaA preclinical non-GMP ADC Drug Substance and clinical GMP Drug Substance for use in clinical trials associated with one of the antibodies designated under the Merck KGaA Agreement. The Company receives fees for its efforts under the Merck KGaA Supply Agreement and reimbursement equal to the supply cost. The Company may also enter into future supply agreements to provide clinical supply material should Merck KGaA pursue clinical development of any other candidates nominated under the Merck KGaA Agreement.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Accounting Analysis</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company identified the following performance obligations under the Merck KGaA agreement: (i) exclusive license and research services for six designated targets, (ii) rights to future technological improvements and (iii) participation of project team leaders and providing joint research committee services.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company is recognizing revenue related to the exclusive license and research and development services over the estimated period of the research and development services using a proportional performance model.  The Company measures proportional performance based on the costs incurred relative to the total costs expected to be incurred. To the extent that the Company receives fees for the research services as they are performed, these amounts are recorded as deferred revenue. <ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:RevenuePerformanceObligationDescriptionOfTiming" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMjE5OTAyMzI2NTEzOA_efccdaab-441b-4289-816e-4e20027f4d13">Revenue related to future technological improvements and joint research committee services will be recognized ratably over the respective performance period (which in the case of the joint research committee services approximates the time and cost incurred each period), which are 10 and five years, respectively.</ix:nonNumeric>&#160;The Company is continuing to reassess the estimated remaining term at each subsequent reporting period. As of December 31, 2019, the total transaction price for the Merck KGaA Agreement was $<ix:nonFraction unitRef="usd" contextRef="i112e393abf7545e0a3ce91e47dbc01e0_I20191231" decimals="-3" format="ixt:numdotdecimal" name="mrsn:RevenueTransactionPriceAmount" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzQ2Ng_cc0646f5-4413-469f-9a5e-c7d7ddfb340e">21,500</ix:nonFraction>, which represented the amount of consideration the Company was expected to receive for the transfer of goods and services to Merck KGaA. During the nine months ended September&#160;30, 2020, the Company decreased the fees expected to be received for research and development activities by $<ix:nonFraction unitRef="usd" contextRef="idd6f25b9e2a34983b244f73682e62ecc_D20200101-20200930" decimals="-3" sign="-" name="mrsn:RevenueTransactionPriceIncreaseDecrease" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzc0MA_41b2858b-28fe-4788-8c58-17b6c683ba16">175</ix:nonFraction> to $<ix:nonFraction unitRef="usd" contextRef="icd7ccd1339114bfaaaa1f1e9ebd9c9f9_I20200930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ReimbursableExpenseResearchAndDevelopmentEstimated" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzc0Ng_88bea92d-dca8-4948-9834-7752ce585f57">6,325</ix:nonFraction>, resulting in a revised total transaction price for the Merck KGaA Agreement of $<ix:nonFraction unitRef="usd" contextRef="icd7ccd1339114bfaaaa1f1e9ebd9c9f9_I20200930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:RevenueTransactionPriceAmount" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzgyOQ_8741bf24-595b-40be-b56b-0cdc57c17b39">21,325</ix:nonFraction>.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the nine months ended September&#160;30, 2020, the Company completed its performance obligations associated with <ix:nonFraction unitRef="target" contextRef="idd6f25b9e2a34983b244f73682e62ecc_D20200101-20200930" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:CollaborationArrangementsTargetsDesignatedPerformanceObligationsSatisfiedNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzkzOQ_816f4ac4-9a9b-4c7a-9125-a4f93e30609b">one</ix:nonFraction> of the <ix:nonFraction unitRef="target" contextRef="icd7ccd1339114bfaaaa1f1e9ebd9c9f9_I20200930" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:CollaborationArrangementsTargetsDesignatedNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzk0OQ_dc5aceb1-6c96-4859-b505-66e0740af5bf">six</ix:nonFraction> designated targets. For the three months ended September&#160;30, 2020 and 2019, and the nine months ended September&#160;30, 2020 and 2019, the Company recorded collaboration revenue of $<ix:nonFraction unitRef="usd" contextRef="i1c58a80956184028809436f54a8cc3f6_D20200701-20200930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDA4OA_683ef193-07cc-4280-a9c6-e0152c8551f7">11</ix:nonFraction>, $<ix:nonFraction unitRef="usd" contextRef="i6c2f5d44cf084792afac22dc943aff6a_D20190701-20190930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDA5Mw_84868ea0-6707-40a6-82bb-e220fe04808a">800</ix:nonFraction>, $<ix:nonFraction unitRef="usd" contextRef="idd6f25b9e2a34983b244f73682e62ecc_D20200101-20200930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDA5Nw_b6ce52c5-e9c8-4157-af52-cf6392062f59">817</ix:nonFraction>, and $<ix:nonFraction unitRef="usd" contextRef="i55f259a24bf846c8b2fbd96fac1af4c3_D20190101-20190930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDEwNQ_e18335f8-c06c-4a03-8285-f1e4c13ab541">836</ix:nonFraction>, respectively, related to its efforts under the Merck KGaA Agreement. During the three and nine months ended </span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">12</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i6aa3f564799840c3851a665b2db62c37" continuedAt="i0cc32ace6151472f9b3bf98e2a7a33fd"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2019, the Company recognized $<ix:nonFraction unitRef="usd" contextRef="ia44fa7077fed466f8179374091432e5b_D20190701-20190930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDIzMg_2599d50f-0b3e-49ac-add5-24d339ba610f">34</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="ib04589411c0446c3a83b1ab57bb103f2_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDIzOQ_3a38fc83-f35e-4841-aeca-81e5c38e5b50">1,255</ix:nonFraction>, respectively, in collaboration revenue and corresponding research and development expense of $<ix:nonFraction unitRef="usd" contextRef="ia44fa7077fed466f8179374091432e5b_D20190701-20190930" decimals="-3" name="us-gaap:ResearchAndDevelopmentExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDMzNg_cc83c114-30aa-4458-b77c-6cfed740d185">34</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="ib04589411c0446c3a83b1ab57bb103f2_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ResearchAndDevelopmentExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDM0Mw_58b09655-dbba-4621-a5c1-f802539a5b49">1,255</ix:nonFraction>, respectively, related to the Merck KGaA Supply Agreement.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020 and December&#160;31, 2019, the Company had $<ix:nonFraction unitRef="usd" contextRef="i1349bd21c10d4879a9f43a68a6e89070_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDQzOA_cbf08c11-1112-4a68-b26f-643c59fa7d1f">3,998</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="i748ce2352838462eb88b38214bb3e1c3_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNDQ0NQ_a4086f59-b36c-49bb-af85-136f3a1d5261">4,815</ix:nonFraction>, respectively, in deferred revenue related to the Merck KGaA Agreement and Merck KGaA Supply Agreement that will be recognized over the remaining performance period.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Takeda XMT-1522 Strategic Partnership</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In January 2016, the Company entered into a Development Collaboration and Commercial License Agreement with Takeda's wholly owned subsidiary, Millennium Pharmaceuticals, Inc. for the development and commercialization of XMT-1522 (the XMT-1522 Agreement). Under the XMT-1522 Agreement, Takeda was granted the exclusive right to commercialize XMT-1522 outside of the United States and Canada. Under the XMT-1522 Agreement, the Company was responsible for conducting certain Phase 1 development activities for XMT-1522, including the ongoing Phase 1 clinical trial, at its own expense. The parties agreed to collaborate on the further development of XMT-1522 in accordance with a global development plan (Post-Phase 1 Development). On January 2, 2019, the Company received notice from Takeda stating that Takeda was exercising its right to terminate the XMT-1522 Agreement upon <ix:nonNumeric contextRef="ifefaa52ae0b34729979e3946e5a1a5af_D20190102-20190102" format="ixt-sec:durday" name="mrsn:CollaborationArrangementsDurationToTermination" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNTUyNw_42803428-96c4-49d3-957c-5aafa694a0b7">30</ix:nonNumeric> days&#8217; prior written notice. The XMT-1522 Agreement terminated in accordance with its provisions, and the Company and Takeda wound down activities related to the XMT-1522 Agreement as of March 31, 2019. Under the XMT-1522 Agreement, the Company and Takeda shared equally all budgeted Post-Phase 1 Development costs through the date of termination and for a period of <ix:nonNumeric contextRef="ifefaa52ae0b34729979e3946e5a1a5af_D20190102-20190102" format="ixt-sec:durday" name="mrsn:CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNTg4Nw_fb24ff28-48cb-4c06-8031-3a8d9ef99de7">30</ix:nonNumeric> days after the effective termination date.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For the applicable period within the three months ended March 31, 2019, the Company was billed $<ix:nonFraction unitRef="usd" contextRef="ie15bbff9fad74d7386b17814d00a5e75_D20190101-20190331" decimals="-3" name="us-gaap:ResearchAndDevelopmentExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNjAyOA_808e3cc9-460d-42ff-b326-237a81f07a25">200</ix:nonFraction> by Takeda, representing the Company&#8217;s share of Post-Phase 1 Development costs incurred by Takeda. This amount has been reflected as research and development costs in the consolidated statement of operations.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Takeda strategic research and development partnership</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In March 2014, the Company entered into a Research Collaboration and Commercial License Agreement with Takeda through Takeda&#8217;s wholly owned subsidiary, Millennium Pharmaceuticals, Inc. (the 2014 Agreement). The 2014 Agreement was amended in January 2015 and amended and restated in January 2016 (the 2016 Restated Agreement). The agreements provided Takeda with the right to develop ADCs directed to a total of <ix:nonFraction unitRef="target" contextRef="i5db68e4812c246888eb694f81bb48fec_I20160131" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:CollaborativeArrangementsExclusiveTargetsNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNjcwNA_1bac0f62-c83d-4020-a525-7ce285d4bd07">seven</ix:nonFraction> exclusive targets, designated by Takeda, over a specified period of time. On January 2, 2019, the Company received notice from Takeda stating that Takeda was exercising its right to terminate the 2016 Restated Agreement upon <ix:nonNumeric contextRef="i09fed9065d504217b4153a5398fa03cc_D20190102-20190102" format="ixt-sec:durday" name="mrsn:CollaborationArrangementsDurationToTermination" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNjkzMg_853c3f7e-2b42-4a94-97ce-851c2687f599">45</ix:nonNumeric> days&#8217; prior written notice. The 2016 Restated Agreement terminated in accordance with its provisions, and the Company and Takeda wound down activities related to the 2016 Restated Agreement as of March 31, 2019.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the applicable period within the three months ended March 31, 2019, the Company billed Takeda $<ix:nonFraction unitRef="usd" contextRef="i158b8b2e0295434286050c8dd84cce8c_D20190101-20190331" decimals="-3" name="mrsn:CollaborationArrangementsCostsBilled" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNzI0OA_3c88bab6-1e94-4f9e-ae71-4354586a66bd">195</ix:nonFraction> related to ASC 808 costs.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Accounting Analysis</span></div><div style="margin-bottom:12pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company&#8217;s collaboration agreements with Takeda were terminated following receipt of written notices during the first quarter of 2019. As there are no further performance obligations, the Company recognized the remaining deferred revenue of</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> $<ix:nonFraction unitRef="usd" contextRef="i661bd2f150a14e4187f1345b75ecb953_D20190101-20190331" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiabilityRevenueRecognized" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNzU0MQ_c407c536-c56e-47d0-93de-59f5e57108b6">39,965</ix:nonFraction> </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">related to the termination of the Takeda agreements in the</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> first quarter of 2019.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Included in accounts payable as of September&#160;30, 2020 and December&#160;31, 2019 was $<ix:nonFraction unitRef="usd" contextRef="id9113a30ecd247e9bab1f6a7a16b66e7_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccountsPayableCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNzY3NQ_61bdb9e5-f95c-4e1a-b4fc-107f9c478cae"><ix:nonFraction unitRef="usd" contextRef="i2ffbb4f4139e44fe963e847067c22d57_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccountsPayableCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfNzY3NQ_b102f3a3-6459-4f02-b971-254c294a011f">2,335</ix:nonFraction></ix:nonFraction> related to the Takeda agreements.</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">13</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i0cc32ace6151472f9b3bf98e2a7a33fd"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Summary of Contract Assets and Liabilities</span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ContractWithCustomerAssetAndLiabilityTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfOTMxNw_709fdaa5-2058-4e3d-a246-96b8dffe41b9" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents changes in the balances of our contract assets and liabilities during the nine months ended September&#160;30, 2020 and 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"></td><td style="width:45.127%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.744%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>Beginning<br/>of Period</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Additions</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Deductions</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>End of Period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Nine months ended September 30, 2020</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract assets</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:ContractWithCustomerAssetNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOmIzZjYwZjlhNjlmNDQxYjM4NTM1YmJjN2UzNzhkN2MwL3RhYmxlcmFuZ2U6YjNmNjBmOWE2OWY0NDFiMzg1MzViYmM3ZTM3OGQ3YzBfMi0xLTEtMS0w_8d4a9974-983f-488f-a729-98c105f9f477">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:zerodash" name="us-gaap:ContractWithCustomerAssetNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOmIzZjYwZjlhNjlmNDQxYjM4NTM1YmJjN2UzNzhkN2MwL3RhYmxlcmFuZ2U6YjNmNjBmOWE2OWY0NDFiMzg1MzViYmM3ZTM3OGQ3YzBfMi03LTEtMS0w_b3706109-d5f4-4021-9608-e1df6aad3898">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract liabilities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOmIzZjYwZjlhNjlmNDQxYjM4NTM1YmJjN2UzNzhkN2MwL3RhYmxlcmFuZ2U6YjNmNjBmOWE2OWY0NDFiMzg1MzViYmM3ZTM3OGQ3YzBfNC0xLTEtMS0w_a595601e-0b47-47c8-9255-346f3ad006ab">4,815</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:zerodash" name="mrsn:ContractWithCustomerLiabilityIncrease" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOmIzZjYwZjlhNjlmNDQxYjM4NTM1YmJjN2UzNzhkN2MwL3RhYmxlcmFuZ2U6YjNmNjBmOWE2OWY0NDFiMzg1MzViYmM3ZTM3OGQ3YzBfNC0zLTEtMS0w_3a983b22-9a22-4f3c-8d42-9ae0d5bca968">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="mrsn:ContractWithCustomerLiabilityDecrease" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOmIzZjYwZjlhNjlmNDQxYjM4NTM1YmJjN2UzNzhkN2MwL3RhYmxlcmFuZ2U6YjNmNjBmOWE2OWY0NDFiMzg1MzViYmM3ZTM3OGQ3YzBfNC01LTEtMS0w_76d4df39-5e0c-4087-8870-e98acedc3066">817</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOmIzZjYwZjlhNjlmNDQxYjM4NTM1YmJjN2UzNzhkN2MwL3RhYmxlcmFuZ2U6YjNmNjBmOWE2OWY0NDFiMzg1MzViYmM3ZTM3OGQ3YzBfNC03LTEtMS0w_1b043aa4-359a-469b-8497-cd773cfd88ce">3,998</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div style="margin-bottom:12pt"><span><br/></span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"></td><td style="width:45.127%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.744%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td 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Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>End of Period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Nine months ended September 30, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract assets</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i741a90802bca471c9476b10ae9bdc2e8_I20181231" decimals="-3" format="ixt:zerodash" name="us-gaap:ContractWithCustomerAssetNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjY1MzNhMzBmNjhlYTQwM2I5NDliNGQ5ZmY4MzEyMDY1L3RhYmxlcmFuZ2U6NjUzM2EzMGY2OGVhNDAzYjk0OWI0ZDlmZjgzMTIwNjVfMi0xLTEtMS0w_e83c0dd4-fc32-44f8-96bd-e1701a7ec53b">&#8212;</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ic48446a1712f42aab763e9766cd66f76_I20190930" decimals="-3" format="ixt:zerodash" name="us-gaap:ContractWithCustomerAssetNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjY1MzNhMzBmNjhlYTQwM2I5NDliNGQ5ZmY4MzEyMDY1L3RhYmxlcmFuZ2U6NjUzM2EzMGY2OGVhNDAzYjk0OWI0ZDlmZjgzMTIwNjVfMi03LTEtMS0w_72ee5628-4c50-467c-b53c-c60aa8cbe332">&#8212;</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract liabilities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:zerodash" name="mrsn:ContractWithCustomerLiabilityIncrease" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjY1MzNhMzBmNjhlYTQwM2I5NDliNGQ5ZmY4MzEyMDY1L3RhYmxlcmFuZ2U6NjUzM2EzMGY2OGVhNDAzYjk0OWI0ZDlmZjgzMTIwNjVfNC0zLTEtMS0w_2cfffb72-d247-4402-8763-32d41db391eb">&#8212;</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ContractWithCustomerLiabilityDecrease" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjY1MzNhMzBmNjhlYTQwM2I5NDliNGQ5ZmY4MzEyMDY1L3RhYmxlcmFuZ2U6NjUzM2EzMGY2OGVhNDAzYjk0OWI0ZDlmZjgzMTIwNjVfNC01LTEtMS0w_132e7314-4e05-4c94-bb37-b0a34f590282">41,550</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ic48446a1712f42aab763e9766cd66f76_I20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ContractWithCustomerLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjY1MzNhMzBmNjhlYTQwM2I5NDliNGQ5ZmY4MzEyMDY1L3RhYmxlcmFuZ2U6NjUzM2EzMGY2OGVhNDAzYjk0OWI0ZDlmZjgzMTIwNjVfNC03LTEtMS0w_bdd6dbb3-4abc-472b-a9fd-02b29c8b1b84">4,646</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times 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style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.723%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Revenue recognized in the period from:</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Amounts included in the contract liability at the beginning of the period</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" name="us-gaap:ContractWithCustomerLiabilityRevenueRecognized" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjZlZTJiOTEzODI1YTRjYzQ5MWZmYmQyMGM5YTk5MTYzL3RhYmxlcmFuZ2U6NmVlMmI5MTM4MjVhNGNjNDkxZmZiZDIwYzlhOTkxNjNfMy0xLTEtMS0w_86d9677a-f608-4991-b4c9-73c11f2525e6">11</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:ContractWithCustomerLiabilityRevenueRecognized" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjZlZTJiOTEzODI1YTRjYzQ5MWZmYmQyMGM5YTk5MTYzL3RhYmxlcmFuZ2U6NmVlMmI5MTM4MjVhNGNjNDkxZmZiZDIwYzlhOTkxNjNfMy0zLTEtMS0w_46440547-d110-453d-b9c9-c7bb447bd431">834</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:ContractWithCustomerLiabilityRevenueRecognized" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RhYmxlOjZlZTJiOTEzODI1YTRjYzQ5MWZmYmQyMGM5YTk5MTYzL3RhYmxlcmFuZ2U6NmVlMmI5MTM4MjVhNGNjNDkxZmZiZDIwYzlhOTkxNjNfMy01LTEtMS0w_07abfcc7-8ac9-47ba-bca5-0588b79af800">817</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New 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colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:zerodash" name="us-gaap:ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod" scale="3" 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For the three and nine months ended September&#160;30, 2019, the Company recognized $<ix:nonFraction unitRef="usd" contextRef="i6091bbf1c3f04444a6a846958a4d685e_D20190701-20190930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfMzI5ODUzNDg5MjcxMg_8733d1e1-5e64-4cbb-a2a4-597dadbf0ccd">10</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="iccb390897b7a4dec86201b227ab189b2_D20190101-20190930" decimals="-3" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfODI1MA_84a96e60-8f54-4a5d-8937-60203f37ae5c">25</ix:nonFraction>, respectively, of revenue related to these services. The Company did <ix:nonFraction unitRef="usd" contextRef="i61e875a9b96e4d7e94a976b847a025b2_D20200701-20200930" decimals="INF" format="ixt-sec:numwordsen" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfODMwNw_196e1bd7-7da0-476e-a958-c4fe559b8edf"><ix:nonFraction unitRef="usd" contextRef="i6b9e698b1f764513ab7470835104fdcf_D20200101-20200930" decimals="INF" format="ixt-sec:numwordsen" name="us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfODMwNw_4c175391-feec-489e-a629-21c28dc64bcc">no</ix:nonFraction></ix:nonFraction>t recognize any revenue related to these services for the three and nine months ended September&#160;30, 2020. The next potential milestone the Company is eligible to receive is $<ix:nonFraction unitRef="usd" contextRef="id40f27e437c4461eacd9fca48ece79a4_I20200930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:CollaborationArrangementsMilestonePaymentReceivableNextMilestone" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfODQ5MQ_13d055a4-4ddf-4cba-bb07-44efdcb75ff2">2,500</ix:nonFraction> upon dosing the fifth patient in a Phase 1 clinical study by Asana BioSciences. As of September&#160;30, 2020, the Company considers this next milestone to be fully constrained as there is considerable judgment involved in determining whether it is probable that a significant revenue reversal would occur. As part of its evaluation of the constraint, the Company considered numerous factors, including the fact that achievement of the milestone is outside the control of the Company and there is a high level of uncertainty in achieving this milestone, as this would require successful initiation of clinical trials by the collaboration partner. The Company reevaluates the probability of achievement of a milestone subject to constraint at each reporting period and as uncertain events are resolved or other changes in circumstances occur.</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">14</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_52"></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">4.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:FairValueMeasurementInputsDisclosureTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RleHRyZWdpb246MGFhOWY2YmFhYTA3NDhhZWIzY2RlZjE5NDY5M2YyM2RfOTMw_7425975d-1922-4f3a-bb9b-4386bde00554" continuedAt="i89886fae314a466f90885d92daf4ba38" escape="true">Fair value measurements</ix:nonNumeric></span></div><ix:continuation id="i89886fae314a466f90885d92daf4ba38"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RleHRyZWdpb246MGFhOWY2YmFhYTA3NDhhZWIzY2RlZjE5NDY5M2YyM2RfOTMx_5592dd32-831e-4153-8af9-645356e3b0ed" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents information about the Company's assets and liabilities regularly measured and carried at a fair value and indicates the level within fair value hierarchy of the valuation techniques utilized to determine such value as of December&#160;31, 2019. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company had no marketable securities as of </span><span style="color:#000000;font-family:'Times New 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style="width:1.0%"></td><td style="width:11.744%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Fair<br/>Value</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Quoted&#160;Prices<br/>in&#160;Active<br/>Markets<br/>(Level&#160;1)</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Significant<br/>Other<br/>Observable<br/>Inputs<br/>(Level&#160;2)</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Significant<br/>Unobservable<br/>Inputs<br/>(Level&#160;3)</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"></td><td 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i3f24028a614e421ca93bbfa43dba6cee_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfMy01LTEtMS0w_893e8684-f3cb-4e89-a8ed-dd3c64630d50">11,940</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ie6d53698ab19442d983f0a404d59dcbd_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfMy03LTEtMS0w_81891a84-8d4a-4b46-a6ac-40d8b80e4376">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Corporate bonds</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03029a4aef3d47fa99bc2837c3e9b70d_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNC0xLTEtMS0w_111e42e1-56de-4469-8f11-dd7f009ff5ec">12,010</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="idb1efacc14c64d0194b3d75acee2f694_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNC0zLTEtMS0w_f885f178-1b42-4e9a-a7a2-344c9b1fb10d">&#8212;</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id9e27b340f124a0192e09d0163f16649_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNC01LTEtMS0w_e869a115-1397-468c-b4e8-3e0e19fad5bb">12,010</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i0ff7c89f3d564b16a55c969cbe4d30a9_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNC03LTEtMS0w_49411c40-268c-4a99-8792-b8696a185e7b">&#8212;</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">U.S. Treasuries</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id1dbd2560ef04c74a2ba084cee432428_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNS0xLTEtMS0w_c96298ce-3cbc-4238-a807-ddd41197cb35">13,489</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="ieefbcd853f2645ac8f2651a602177617_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNS0zLTEtMS0w_de95bc19-cc5f-430d-834e-e44a1fa79a70">13,489</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i8b960bf6cdc64f52b3d1f035903b2345_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNS01LTEtMS0w_656d7419-5080-47da-b590-f7d593949049">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="icd3da95d2caf4eeb98ac76e1680060e8_I20191231" decimals="-3" format="ixt:zerodash" name="us-gaap:AvailableForSaleSecuritiesDebtSecurities" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNS03LTEtMS0w_833a78b7-d112-4118-99cf-7f442653e672">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RhYmxlOjI4YjUxMGRmNjgzYzQ4NDNhYmUxMWZiYWJjYjgxZjQzL3RhYmxlcmFuZ2U6MjhiNTEwZGY2ODNjNDg0M2FiZTExZmJhYmNiODFmNDNfNi0zLTEtMS0w_30bb01f7-40ef-4ec4-b89a-d4e6a8653d8e">13,489</ix:nonFraction>&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times 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0;text-align:right;vertical-align:bottom"></td></tr></table></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">There were no changes in valuation techniques or transfers between fair value measurement levels during the nine months ended September&#160;30, 2020 and 2019. </span></div><div style="margin-bottom:12pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The carrying amounts reflected in the consolidated balance sheets for prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values due to their short-term nature.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, the carrying 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contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81NS9mcmFnOmFlZmE3M2RhZTBlNDRiMjRhZjFlZTQyM2M5ODE5MWFkL3RleHRyZWdpb246YWVmYTczZGFlMGU0NGIyNGFmMWVlNDIzYzk4MTkxYWRfMTk5_5cce9e0f-459e-4103-a1c5-7cd2e4502696" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table summarizes marketable securities held at December&#160;31, 2019. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company had <ix:nonFraction unitRef="security" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt-sec:numwordsen" 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style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.741%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.602%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.744%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Amortized<br/>Cost</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">15</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_58"></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">6.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RleHRyZWdpb246YWJkZGRkY2Q5MzkwNDM2YmE4Yjc3ZDE2YjAwZjI1NTlfODg_db9d3d53-3df9-4004-8419-046ff492d108" continuedAt="i00b366e6bf1649c2be72c52779096548" escape="true">Accrued expenses</ix:nonNumeric></span></div><ix:continuation id="i00b366e6bf1649c2be72c52779096548"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RleHRyZWdpb246YWJkZGRkY2Q5MzkwNDM2YmE4Yjc3ZDE2YjAwZjI1NTlfODk_9f18a5be-5abb-4d8f-aefa-bdeb6125fb66" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Accrued expenses consisted of the following as of September&#160;30, 2020 and December&#160;31, 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued payroll and related expenses</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:EmployeeRelatedLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RhYmxlOjU0MTZjNTEyYjI5NzQ2NTliMDIxNTkzYjYzYmM2Y2IyL3RhYmxlcmFuZ2U6NTQxNmM1MTJiMjk3NDY1OWIwMjE1OTNiNjNiYzZjYjJfMS0zLTEtMS0w_52871e44-b3a2-4849-a31a-e56b40dee07f">4,037</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued preclinical, manufacturing and clinical expenses</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:AccruedPreclinicalAndClinicalExpensesCurrent" scale="3" 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RhYmxlOjU0MTZjNTEyYjI5NzQ2NTliMDIxNTkzYjYzYmM2Y2IyL3RhYmxlcmFuZ2U6NTQxNmM1MTJiMjk3NDY1OWIwMjE1OTNiNjNiYzZjYjJfMi0zLTEtMS0w_df1381c1-436d-48b7-91e7-c72d129c0e33">4,230</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued professional fees and insurance</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="mrsn:AccruedProfessionalFeesAndInsuranceCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RhYmxlOjU0MTZjNTEyYjI5NzQ2NTliMDIxNTkzYjYzYmM2Y2IyL3RhYmxlcmFuZ2U6NTQxNmM1MTJiMjk3NDY1OWIwMjE1OTNiNjNiYzZjYjJfMy0xLTEtMS0w_81c21096-f97f-4873-9831-6af7a4e4e51a">861</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" name="mrsn:AccruedProfessionalFeesAndInsuranceCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RhYmxlOjU0MTZjNTEyYjI5NzQ2NTliMDIxNTkzYjYzYmM2Y2IyL3RhYmxlcmFuZ2U6NTQxNmM1MTJiMjk3NDY1OWIwMjE1OTNiNjNiYzZjYjJfMy0zLTEtMS0w_9d3ce435-daaf-428e-87a0-7b78d2e5a6c1">675</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued other</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:OtherAccruedLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RhYmxlOjU0MTZjNTEyYjI5NzQ2NTliMDIxNTkzYjYzYmM2Y2IyL3RhYmxlcmFuZ2U6NTQxNmM1MTJiMjk3NDY1OWIwMjE1OTNiNjNiYzZjYjJfNC0xLTEtMS0w_60b0dadb-0bf4-44f7-af12-b1c23600fd5b">65</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 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1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccruedLiabilitiesCurrent" scale="3" 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#000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AccruedLiabilitiesCurrent" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81OC9mcmFnOmFiZGRkZGNkOTM5MDQzNmJhOGI3N2QxNmIwMGYyNTU5L3RhYmxlOjU0MTZjNTEyYjI5NzQ2NTliMDIxNTkzYjYzYmM2Y2IyL3RhYmxlcmFuZ2U6NTQxNmM1MTJiMjk3NDY1OWIwMjE1OTNiNjNiYzZjYjJfNS0zLTEtMS0w_cd07d23d-abd8-47fe-9568-ae897399e349">8,986</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div></ix:nonNumeric></ix:continuation><div style="margin-bottom:12pt"><span><br/></span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_64"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">7.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:DebtDisclosureTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTQxMw_08b0afe9-19b2-4993-bd88-6236e17118ff" continuedAt="ic64ca53527064a4c9ac3c60a1aa0eee0" escape="true">Debt</ix:nonNumeric></span></div><ix:continuation id="ic64ca53527064a4c9ac3c60a1aa0eee0" continuedAt="i8c565f7c9be144738ab07cd1ca06a30c"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On May 8, 2019, the Company entered into a loan and security agreement (the Original Agreement) with Silicon Valley Bank (SVB) pursuant to which the Company borrowed $<ix:nonFraction unitRef="usd" contextRef="i14b54665913f425891b53a926b026a6c_D20190508-20190508" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ProceedsFromLinesOfCredit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTg4OA_c115b43b-6f6b-4f18-8b09-03658060f243">5,000</ix:nonFraction>. The Original Agreement accrued interest at a floating per annum rate equal to the greater of (i) <ix:nonFraction unitRef="number" contextRef="i62488664b6a8416cb1e82804bc1c48b3_I20190508" decimals="INF" name="us-gaap:DebtInstrumentInterestRateStatedPercentage" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEzOA_a64c1226-ef23-47f6-8ed2-ae64338432fc">4.0</ix:nonFraction>% and (ii) <ix:nonFraction unitRef="number" contextRef="ib1fde3a2cf594b0fbb35aa7a7923d373_D20190508-20190508" decimals="INF" sign="-" name="us-gaap:DebtInstrumentBasisSpreadOnVariableRate1" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzE0NA_ec8b37a9-6e47-4e6c-bf3c-08103bf27b13">1.50</ix:nonFraction>% below the Prime Rate. The Original Agreement had an interest-only period through August 31, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On August 28, 2020 (the Effective Date), the Company entered into a second amendment (the Amendment)</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> to its existing loan and security agreement (as amended prior to the Amendment, the Existing Credit Facility) with </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">SVB. Pursuant to the Amendment, the Company can borrow term loans in an aggregate amount of $<ix:nonFraction unitRef="usd" contextRef="iacf0da2eacac4227b0377970d5181b2a_I20200828" decimals="-6" format="ixt:numdotdecimal" name="us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTA5OTUxMTYzOTIxNg_d9adf03c-4946-4896-9171-9728616db66a">30,000</ix:nonFraction> (the Amended Credit Facility), at its option, </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(i) up to $<ix:nonFraction unitRef="usd" contextRef="ib0c549eb28e64381be74b1a6f5851ac4_I20200828" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTg5OQ_003a63c1-9ea2-43a7-b00d-4e694f89c935"><ix:nonFraction unitRef="usd" contextRef="i7adaecb63b204f299897a943df12c80a_I20200828" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTg5OQ_232f518e-1783-45ac-8bb8-f2efe470b66a"><ix:nonFraction unitRef="usd" contextRef="i6d3722e50dde450b841244c9f5de6d41_I20200828" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTg5OQ_4c675865-21da-4f1d-ae54-60a59866d03f"><ix:nonFraction unitRef="usd" contextRef="i62b52bd826ed44a39cf1f71d54a4122e_I20200828" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTg5OQ_7e0b5777-39d6-49bd-9c33-a91e35f74275"><ix:nonFraction unitRef="usd" contextRef="i5a32ea82f8454da198d31cac85811819_I20200828" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:LineOfCreditFacilityMaximumBorrowingCapacity" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTg5OQ_fb3b822a-c510-415b-9e11-2d52ff18ece2">25,000</ix:nonFraction></ix:nonFraction></ix:nonFraction></ix:nonFraction></ix:nonFraction> in up to five principal advances through April 30, 2022, and (ii) an additional $<ix:nonFraction unitRef="usd" contextRef="i1360e2634a424f4494fc11c20d4be8d3_I20200828" decimals="INF" format="ixt:numdotdecimal" name="mrsn:LineOfCreditFacilityAccordianFeatureIncreaseLimit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTkxOA_933617a6-7f4d-4c34-ab4a-eb6aa2e25cfb">5,000</ix:nonFraction> in one principal advance, if the Company reaches certain development milestone events, as described in the Amendment, through April 30, 2022. The Company drew $<ix:nonFraction unitRef="usd" contextRef="i20a0178a16b44a089b3366764b8ff83d_D20200828-20200828" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ProceedsFromLinesOfCredit" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTkyOQ_cb7245cc-c8b3-4245-b777-735e6767d56a">5,200</ix:nonFraction> upon execution of the Amendment, the proceeds of which were used to repay the Company&#8217;s existing balance and satisfy its obligations to SVB, including the final payment obligation under the Existing Credit Facility.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Amended Credit Facility bears interest at a floating per annum rate equal to the greater of (i) <ix:nonFraction unitRef="number" contextRef="i4109dc7760cf49ef90e9300801ed9193_I20200828" decimals="INF" name="us-gaap:DebtInstrumentInterestRateStatedPercentage" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzA5NA_3694f103-a67c-4275-aebd-7c53e63c855a">4.25</ix:nonFraction>% and (ii) <ix:nonFraction unitRef="number" contextRef="i56b9e89a6fd544869019fe74d1805957_D20200828-20200828" decimals="INF" name="us-gaap:DebtInstrumentBasisSpreadOnVariableRate1" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEwMQ_6242d54e-3399-4956-987a-c6988b850fac">1.00</ix:nonFraction>% above the Prime Rate, as defined. The Company is obligated to make monthly interest-only payments on each outstanding term loan commencing on the first calendar day of the month following the funding date of such term loan, and continuing on the first calendar day of each month thereafter through May 31, 2022. The interest only period may be extended through January 31, 2023 upon the achievement of a regulatory milestone, as described in the Amendment. Following the interest-only period, the Company will be required to repay the outstanding principal balance under the term loans in equal monthly payments plus interest in arrears to SVB through November 1, 2024 (the Maturity Date).</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company is also required to make a final payment to SVB equal to <ix:nonFraction unitRef="number" contextRef="i20a0178a16b44a089b3366764b8ff83d_D20200828-20200828" decimals="INF" name="mrsn:DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEwOA_dc06da9c-2070-4168-82da-37b115d55df6">5.5</ix:nonFraction>% of the original principal amount of the term loans then extended to the Company. This final payment is accreted under the effective interest method over the life of each term loan. The term loans are secured by substantially all of the Company's assets, except for its intellectual property which is subject to a negative pledge, and certain other customary exclusions.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">At the Company&#8217;s option, it may prepay the outstanding principal balance of any term loans in whole but not in part, subject to a prepayment fee of: (a) <ix:nonFraction unitRef="number" contextRef="i5618dcb2bf4349d7bbc92a2fd0ef6975_D20200828-20200828" decimals="INF" name="mrsn:DebtInstrumentPrepaymentFeePercentage" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzExNA_bbf91713-28aa-426d-8a5f-6f1fafc59c5e">3.0</ix:nonFraction>% of the term loans then extended to the Company if the prepayment occurs on or prior to August 28, 2021, (b) <ix:nonFraction unitRef="number" contextRef="i1a2382de89694608bd0ddd7aaaafa1b1_D20200828-20200828" decimals="INF" name="mrsn:DebtInstrumentPrepaymentFeePercentage" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEyMA_89348d13-d559-4b38-ab80-2f7686538353">2.0</ix:nonFraction>% of the term loans then extended to the Company if the prepayment occurs after August 28, 2021 but on or prior to August 28, 2022, or (c) <ix:nonFraction unitRef="number" contextRef="i476b73e3ee3e480ab3006d6fb3bed77e_D20200828-20200828" decimals="INF" name="mrsn:DebtInstrumentPrepaymentFeePercentage" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEyNg_0ecd8abf-be37-488a-a0b5-d967a8732d0c">1.0</ix:nonFraction>% of the term loans then extended to the Company if the prepayment occurs after August 28, 2022 but before November 1, 2024. The Amended Credit Facility includes customary affirmative and restrictive covenants applicable to the Company. Affirmative covenants include, among others, covenants requiring the Company to maintain its corporate existence and governmental approvals, deliver certain financial reports, maintain insurance coverage and satisfy certain requirements regarding </span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">16</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i8c565f7c9be144738ab07cd1ca06a30c" continuedAt="i7c3e62bea649448698bc18c328f7ebb4"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">deposit accounts. The Amendment removed the requirement for the Company to maintain a minimum liquidity ratio. The restrictive covenants include, among others, requirements relating to the Company&#8217;s ability to transfer collateral, incur additional indebtedness, engage in mergers or acquisitions, pay dividends or make other distributions, make investments, create liens, sell assets and agree to a change in control, in each case subject to certain customary exceptions.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company&#8217;s payment obligations under the Amended Credit Facility are subject to acceleration upon the occurrence of specified events of default, which include, but are not limited to, the occurrence of a material adverse change in the Company&#8217;s business, operations, or financial or other condition. Amounts outstanding upon the occurrence of an event of default are payable upon SVB&#8217;s demand and shall accrue interest at an additional rate of <ix:nonFraction unitRef="number" contextRef="i20a0178a16b44a089b3366764b8ff83d_D20200828-20200828" decimals="INF" name="mrsn:DebtInstrumentDebtDefaultAdditionalRate" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEzMg_f29e1555-8ab6-4735-b437-2e2e2740cd31">5.0</ix:nonFraction>% per annum of the past due amount outstanding. As of September&#160;30, 2020, the Company was in compliance with all covenants under the Amended Credit Facility. As such, as of September&#160;30, 2020, the classification of the loan balance as stated on the balance sheet was based on the timing of defined future payment obligations.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The unamortized issuance costs under the Existing Credit Facility were $<ix:nonFraction unitRef="usd" contextRef="i70b4d6bc15744935b8eefe34389bb283_I20200828" decimals="-3" name="us-gaap:DeferredFinanceCostsNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTk0Mw_7f68bdc6-f437-4d41-b1af-5771464ef3de">139</ix:nonFraction> as of the date of the Amendment. The Company incurred debt issuance costs paid to the lender in connection with the Amended Credit Facility of $<ix:nonFraction unitRef="usd" contextRef="iacf0da2eacac4227b0377970d5181b2a_I20200828" decimals="-3" name="us-gaap:DeferredFinanceCostsGross" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTk1Mg_ff53bf36-8940-455d-b797-27ee585c3b03">17</ix:nonFraction>. The Company recorded such costs, including the settlement of the final payment obligation under the Existing Credit Facility as a discount from the carrying value of the term loans which are amortized as interest expense using the effective-interest method over the term of the Amended Credit Facility. </span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfDebtTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2ODg3Mw_bbab4d99-6bf3-4131-94fc-2fcfdc26549d" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, there was $<ix:nonFraction unitRef="usd" 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1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total debt</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Debt financing costs, net of accretion</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:DeferredFinanceCostsNet" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfNC0xLTEtMS0w_bea8f5a8-8540-4df2-8bdb-01c7b9611160">262</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accretion related to final payment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:DebtInstrumentUnamortizedPremium" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfNS0xLTEtMS0w_62388181-5556-45bd-af93-733e6fa43133">6</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Long-term debt, net</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LongTermDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfNi0xLTEtMS0w_f7b27aa1-433e-414c-ab15-20b120005e34">4,944</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid 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style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:zerodash" 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0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOjNjNmY1NDA2OThjMzRkZDM5NzZmMjUzZGRiYjhhMGU4L3RhYmxlcmFuZ2U6M2M2ZjU0MDY5OGMzNGRkMzk3NmYyNTNkZGJiOGEwZThfMy0xLTEtMS0w_dc512c79-a0d7-46d4-bfb6-8b8e17b728a9">2,080</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOjNjNmY1NDA2OThjMzRkZDM5NzZmMjUzZGRiYjhhMGU4L3RhYmxlcmFuZ2U6M2M2ZjU0MDY5OGMzNGRkMzk3NmYyNTNkZGJiOGEwZThfNC0xLTEtMS00NzY_1a5a8d72-765c-4188-85cf-fe611e131efc">1,907</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total debt</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOjNjNmY1NDA2OThjMzRkZDM5NzZmMjUzZGRiYjhhMGU4L3RhYmxlcmFuZ2U6M2M2ZjU0MDY5OGMzNGRkMzk3NmYyNTNkZGJiOGEwZThfNC0xLTEtMS0w_eff3f340-0f40-423d-9dd8-8f23ffc27f64">5,200</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div></ix:nonNumeric></ix:continuation><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:continuation id="i7c3e62bea649448698bc18c328f7ebb4">During the three months ended September&#160;30, 2020 and 2019, and the nine months ended September&#160;30, 2020 and 2019, the Company recognized $<ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="-3" name="us-gaap:InterestExpenseDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTIxOQ_8dda9fb1-c51a-44f9-abc3-3cb882efcb3d">60</ix:nonFraction>, $<ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" name="us-gaap:InterestExpenseDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMzI5ODUzNDg5NjA5NA_2b77489c-b934-499a-b96e-a3596a4ad775">51</ix:nonFraction>, $<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" name="us-gaap:InterestExpenseDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTIyNg_9775036e-4619-4d9d-acba-eea061a42447">173</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:InterestExpenseDebt" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTA5OTUxMTY0MDQwNg_c0297d4d-4efb-49be-897b-bbc384860d61">64</ix:nonFraction>, respectively, of interest expense related to the Existing Credit Facility and Amended Credit Facility, as applicable.</ix:continuation> </span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_67"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">8.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:StockholdersEquityNoteDisclosureTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjkxNA_fa7c8c73-22a4-4b6d-8997-c99256ecbe66" continuedAt="ia045abfd37ab4814b20e236df486255e" escape="true">Stockholders&#8217; equity </ix:nonNumeric></span></div><ix:continuation id="ia045abfd37ab4814b20e236df486255e" continuedAt="ib38d36f8090e4f3e84f5a68bfe0144f5"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Preferred stock</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, the Company had <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:PreferredStockSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNzI_5d278220-2e20-4358-981a-c58044a9a388">25,000,000</ix:nonFraction> shares of authorized preferred stock. <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt-sec:numwordsen" name="us-gaap:PreferredStockSharesIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTEz_1a1f5aa5-6658-4705-8326-dc1d2dd6a6ba">No</ix:nonFraction> shares of preferred stock have been issued.</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">17</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="ib38d36f8090e4f3e84f5a68bfe0144f5" continuedAt="i9f5299429308475fb7f1b9e1e0a84779"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">At-the-market equity offering program</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In July 2018, the Company established an at-the-market (ATM) equity offering program (the 2018 ATM) pursuant to which it offered and sold up to $<ix:nonFraction unitRef="usd" contextRef="i7685808414ad4978b859caa3119386a3_I20180731" decimals="INF" format="ixt:numdotdecimal" name="mrsn:StockIssuanceProgramAuthorizedAmount" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMzM4_3b226875-5c6c-4e8b-80dc-2099382082c8">75,000</ix:nonFraction> of its common stock from time to time at prevailing market prices. In April 2020, the Company sold <ix:nonFraction unitRef="shares" contextRef="i1de5e652c06d43f483fd33670f1c2096_D20200401-20200430" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNDQw_0eda3cc8-c874-457a-9453-03270ebb3103">8,938,599</ix:nonFraction> and <ix:nonFraction unitRef="shares" contextRef="i14aebb01403f434badf0ac414b24682a_D20200401-20200430" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNDQ3_31f5a60c-b47c-4eda-9a1b-6fef27c581d8">1,962,000</ix:nonFraction> shares of common stock at $<ix:nonFraction unitRef="usdPerShare" contextRef="i88dbf16e8883438b99eb7e8eb89cb0d7_I20200430" decimals="INF" name="us-gaap:SharesIssuedPricePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNDc2_a7d3d6b3-44aa-440c-87c3-04f416d5319c">5.59</ix:nonFraction> per share and $<ix:nonFraction unitRef="usdPerShare" contextRef="i225c9a586f9e473a9d3866c359946f58_I20200430" decimals="INF" name="us-gaap:SharesIssuedPricePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNDkz_9c04f6ee-a7dc-48c1-8266-9f09616919eb">7.74</ix:nonFraction> per share, respectively, to raise aggregate gross proceeds of $<ix:nonFraction unitRef="usd" contextRef="ie0c01d25fe5c457bac585a0199b91d06_D20200401-20200430" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ProceedsFromIssuanceOfCommonStockGross" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNTU4_75576e5e-b27e-4c24-9be9-bb8a89e1aa67">65,153</ix:nonFraction> through the 2018 ATM facility. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $<ix:nonFraction unitRef="usd" contextRef="ie0c01d25fe5c457bac585a0199b91d06_D20200401-20200430" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfNzE2_7f80437a-4508-45ea-a800-f56f297fc3b1">62,976</ix:nonFraction>. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In May 2020, the Company terminated the 2018 ATM and established a new ATM equity offering program (the 2020 ATM) pursuant to which it is able to sell up to $<ix:nonFraction unitRef="usd" contextRef="ib0605b778c784c8b84501c38345e2806_I20200531" decimals="INF" format="ixt:numdotdecimal" name="mrsn:StockIssuanceProgramAuthorizedAmount" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfODc0_a38a9640-4a7f-4ff5-b1fd-b48cef770d31">100,000</ix:nonFraction> of its common stock from time to time at prevailing market prices. As of September&#160;30, 2020, the Company had <ix:nonFraction unitRef="shares" contextRef="ifecffbdede0941a68b36943dd47bc9e8_I20200930" decimals="INF" format="ixt-sec:numwordsen" name="us-gaap:SharesIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfOTcw_1f2a7a66-b89d-4aee-bfb1-7b99de3f57a2">no</ix:nonFraction>t sold any shares under the 2020 ATM.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Follow-on offering</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2020, the Company sold <ix:nonFraction unitRef="shares" contextRef="i14c2e05a25d8436dabfbefc31e1a1f13_D20200601-20200630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesNewIssues" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTA1OQ_9036e388-21d6-484e-b360-7e48c80beb6a">9,200,000</ix:nonFraction> shares of common stock, in an underwritten public offering price to the public of $<ix:nonFraction unitRef="usdPerShare" contextRef="i1b86b61b22b143eea3669ff418563851_I20200630" decimals="INF" name="us-gaap:SharesIssuedPricePerShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTE0NA_2a89ec93-5912-415a-bd18-8f0c7e31856b">19.00</ix:nonFraction> per share, resulting in gross proceeds of approximately $<ix:nonFraction unitRef="usd" contextRef="i14c2e05a25d8436dabfbefc31e1a1f13_D20200601-20200630" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ProceedsFromIssuanceOfCommonStockGross" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTIwMw_8d1b562d-38b9-4f1c-874d-a92662f5811c">174,800</ix:nonFraction>. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $<ix:nonFraction unitRef="usd" contextRef="i14c2e05a25d8436dabfbefc31e1a1f13_D20200601-20200630" decimals="-3" format="ixt:numdotdecimal" name="mrsn:ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTMzMQ_bbe65470-f56e-4be4-81d3-1986eacea10e">163,991</ix:nonFraction>.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Warrants</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In connection with a 2013 Series&#160;A-1 Preferred Stock issuance, the Company granted to certain investors warrants to purchase <ix:nonFraction unitRef="shares" contextRef="ib9b1240fbc4f4dc8b88e5f065298d334_D20130101-20131231" decimals="INF" format="ixt:numdotdecimal" name="mrsn:ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTQ2OQ_2b01073e-bd21-483a-9f06-b3d2a4d66a0e">129,491</ix:nonFraction> shares of common stock. The warrants have a $<ix:nonFraction unitRef="usdPerShare" contextRef="i4708f4e461ef44979956817e2884dc3f_I20131231" decimals="INF" name="us-gaap:ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTUxNg_e4b408d5-1729-4f71-87a7-cb723609ac01">0.05</ix:nonFraction> per share exercise price and a contractual life of <ix:nonNumeric contextRef="ib9b1240fbc4f4dc8b88e5f065298d334_D20130101-20131231" format="ixt-sec:duryear" name="mrsn:ContractualLifeOfWarrants" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTU3MA_f5023244-406c-4f65-8098-d72e6006b268">10</ix:nonNumeric> years. The fair value of these warrants was recorded as a component of equity at the time of issuance. As of September&#160;30, 2020, there were warrants to purchase <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTcxMg_bda89c3a-8391-4d5f-8abc-cb2e8a10903f">39,474</ix:nonFraction> shares of common stock.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Exchange warrants</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On November 26, 2019, the Company entered into an exchange agreement with entities affiliated with Biotechnology Value Fund, L.P. (the Exchanging Stockholders), pursuant to which the Exchanging Stockholders exchanged an aggregate of <ix:nonFraction unitRef="shares" contextRef="i4ef91051845f420b9887a415c08e8f04_D20191126-20191126" decimals="INF" format="ixt:numdotdecimal" name="mrsn:ClassOfWarrantOrRightSharesExchangedForWarrants" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMTk5Mg_7cdb2083-3b2f-4c54-86c8-eb8052bdf10a">2,575,000</ix:nonFraction> shares of common stock for warrants (the Exchange Warrants) to purchase an aggregate of <ix:nonFraction unitRef="shares" contextRef="i9cbc9df2177240a7b1f8512c6c7f298c_I20191126" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjA4NQ_36c5df1f-7bf5-4723-ab88-3987c85e3b92">2,575,000</ix:nonFraction> shares of common stock (subject to adjustment in the event of any stock dividends and splits, reverse stock split, merger or consolidation, change of control, reorganization or similar transaction, as described in the Exchange Warrants), with an exercise price of $<ix:nonFraction unitRef="usdPerShare" contextRef="i9cbc9df2177240a7b1f8512c6c7f298c_I20191126" decimals="INF" name="us-gaap:ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjM1Mg_30f847fb-3f57-4782-b874-37a65590a51b">0.0001</ix:nonFraction> per share.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On March 2, 2020, the Exchanging Stockholders exercised the Exchange Warrants in full on a net cashless exercise basis, resulting in the issuance of <ix:nonFraction unitRef="shares" contextRef="ib87ac373d12c45e6910051b2d1fac28e_D20200302-20200302" decimals="INF" format="ixt:numdotdecimal" name="mrsn:WarrantsExercisedInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjUxNQ_e25e3536-ba64-4d3c-b654-007fb82db3db">2,574,971</ix:nonFraction> shares of common stock.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Common stock</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The holders of the common stock are entitled to <ix:nonFraction unitRef="vote" contextRef="i7fe6a5a988fb496dad956679a88047d6_D20200101-20200930" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:NumberOfVotesPerCommonShare" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjYwMw_3cfb3d3f-85cc-4231-9a42-cdf6f0396c90">one</ix:nonFraction> vote for each share held. Common stockholders are not entitled to receive dividends, unless declared by the Board of Directors (the Board).</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">18</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i9f5299429308475fb7f1b9e1e0a84779"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">At September&#160;30, 2020 and December&#160;31, 2019, there were <ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="0" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjc3MQ_641afc96-3aea-469a-b040-926021e4fc39">6,995,704</ix:nonFraction> and <ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="0" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjc3OA_8e9e3e77-7a09-4bff-9062-67aeb463fc64">7,782,582</ix:nonFraction>, respectively, shares of common stock reserved for the exercise of outstanding stock options, restricted stock units and warrants, as follows:</span></div><div style="margin-bottom:12pt"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfStockByClassTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjkxMw_ef02a495-0c1c-448f-84ae-c26a88ab5c0b" escape="true"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="ib68fdc1eb9f449f98da58d733d89ecd5_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfMS0xLTEtMS0w_235b038d-3623-4029-9f65-93b81fdffd07">6,215,368</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i368990fd36b2431ab719d8774215760b_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfMS0zLTEtMS0w_f7ecffdd-7906-4ac5-8ffc-ed06b9d5089c">4,720,772</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted stock units</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="if807d4567b5e4b2a8023c0b69108e43b_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfMi0xLTEtMS0w_9d1e6402-bcfc-442d-a14c-8a8ddbbda938">740,862</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i203454142c744ad98bdc2631a9e659a2_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfMi0zLTEtMS0w_a7e1f61c-3f48-4595-be8c-9f82740b1803">447,336</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Warrants</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i5c0b053ffc5247f28ab29ae8de5b6b08_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfMy0xLTEtMS0w_01ee8963-0b64-4453-89c0-a66494519633">39,474</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 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contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIxNA_b52501b6-2372-4733-b9ad-61e168753f22" continuedAt="ib9ab73433af346c985eff4c5f3b233e6" escape="true">Stock options</ix:nonNumeric></span></div><ix:continuation id="ib9ab73433af346c985eff4c5f3b233e6" continuedAt="ib3e2446ab8ce4da4a552346fbb367ba0"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Stock option plans</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2017, the Company&#8217;s stockholders approved the 2017 Stock Incentive Plan (the 2017 Plan). Under the 2017 Plan, up to <ix:nonFraction unitRef="shares" contextRef="i33418e26f94c4e42b0bb26cc7127be51_I20170630" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTY1_0be965da-55df-4513-9f00-e381781c8161">2,255,000</ix:nonFraction> shares of common stock were initially available to be granted to the Company's employees, officers, directors, consultants and advisors in the form of options, restricted stock units (RSUs) or other stock-based awards. The number of shares of common stock issuable under the 2017 Plan will be cumulatively increased annually by <ix:nonFraction unitRef="number" contextRef="i2ac37f681f33496d83fbf5a54519ec27_D20170601-20170630" decimals="INF" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDk2_50bb5636-8a6a-44aa-869c-e4c3f020e84c">4</ix:nonFraction>% of the outstanding shares or such lesser amount specified by the Board. The terms of the awards are determined by the Board, subject to the provisions of the 2017 Plan. Any cancellations under the 2007 Plan, which expired in June 2017, would increase the number of shares that could be granted under the 2017 Plan. In January 2020, the number of shares of common stock issuable under the 2017 Plan was increased by <ix:nonFraction unitRef="shares" contextRef="i66e0205c6a48410e8a1e394f04476a28_D20200101-20200131" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfOTE0_8107c5af-8e0f-4d4a-a4b3-f6d525b9d70c">1,815,520</ix:nonFraction> shares. As of September&#160;30, 2020, there were <ix:nonFraction unitRef="shares" contextRef="i4d35ac2cf3ab4209948ffcd7e23fad32_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfOTQ2_a66ef8ae-2fe5-4fba-913b-3a58ffe1682c">1,320,916</ix:nonFraction> shares available for future issuance under the 2017 Plan. During the nine months ended September 30, 2020, the Company granted <ix:nonFraction unitRef="shares" contextRef="i3a4cc3e066584ce48e802f0029fd419d_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="mrsn:ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNzE0NjgyNTU4NjcyNw_163e382c-b0fb-4102-bd88-79f08c517606">2,165,306</ix:nonFraction> RSUs and options to purchase shares of common stock to employees under the 2017 Plan. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Inducement awards</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On September 2, 2020, the Company granted its senior vice president of regulatory affairs an option to purchase up to <ix:nonFraction unitRef="shares" contextRef="i36f4748bfb414f2d8e0ed7247a1f0878_D20200902-20200902" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTA5OTUxMTYzMjUyMA_5d388c4d-f532-4b26-8569-a690d0451418">120,000</ix:nonFraction> shares of common stock as an inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4). No underwriters were involved in this issuance of securities. The securities were issued pursuant to Section 4(a)(2) under the Securities Act of 1933, as amended, relating to transactions by an issuer not involving any public offering. These options are subject to terms substantially the same as the 2017 Plan.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">With respect to the stock option grants as described above, the exercise price per share will equal the fair market value of the common stock on the date of grant, and the vesting period is generally <ix:nonNumeric contextRef="ied3ea81ae3464d01b13dca99689cb9cb_D20200101-20200930" format="ixt-sec:durwordsen" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTE4OA_654abecc-9956-43ae-a47b-60cbaf5f9d55">four years</ix:nonNumeric>. Nonqualified stock options will be granted at an exercise price established by the Board at its sole discretion (which has not been less than fair market value on the date of grant) and the vesting periods may vary. Options granted as described above expire no later than <ix:nonNumeric contextRef="i7bbbabae70844350984999f4e64477bb_D20200101-20200930" format="ixt-sec:duryear" name="us-gaap:SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTQ2NQ_01000160-2dc5-4056-9c1f-92884cb011af">10</ix:nonNumeric> years from the date of grant. The Board may accelerate vesting or extend the expiration of granted options in the case of a merger, consolidation, dissolution, or liquidation of the Company.</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">19</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="ib3e2446ab8ce4da4a552346fbb367ba0" continuedAt="i077d72ed9d0d4092a22bf350e3640a50"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Stock option activity</span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIxMg_7c0a5d6b-8bcd-4c24-b96c-4d8e86673f4d" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A summary of the options activity under the Plans is as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Number<br/>of&#160;Shares</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Weighted-<br/>Average<br/>Exercise&#160;Price</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Outstanding at January&#160;1, 2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i99447cccfa554f5fb1ac698db15ddb71_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfMS0xLTEtMS0w_eeeb1029-ee37-4a91-82d7-33a335f03022">4,720,772</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Granted</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfMi0xLTEtMS0w_0f189128-85ba-43f9-84f2-1c02784fe310">1,960,374</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usdPerShare" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfMi0zLTEtMS0w_03c27bd5-feb0-44b7-913e-26def3ee9bd8">9.41</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exercised</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="shares" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:StockIssuedDuringPeriodSharesStockOptionsExercised" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfMy0xLTEtMS0w_7beb9e5e-e66e-48c4-ae9a-23197fce2424">338,069</ix:nonFraction>)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usdPerShare" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfMy0zLTEtMS0w_eb9cdf40-1a3a-4144-a6c1-339f7ebb3aa4">5.13</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cancelled</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="shares" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfNC0xLTEtMS0w_39accad9-7708-4f2f-bdb7-1c0f2de5c54d">127,709</ix:nonFraction>)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usdPerShare" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfNC0zLTEtMS0w_16ea7fee-8c1f-4610-b57a-9137025c1f95">7.70</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Outstanding at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfNS0xLTEtMS0w_6eae2680-cfdc-46bf-9db1-024223fe09b9">6,215,368</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usdPerShare" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfNS0zLTEtMS0w_c08006b1-1293-447c-b61a-8e8a49b128e8">6.52</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exercisable at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfNi0xLTEtMS0w_97fc98dd-d7fe-4afd-9f41-7d61873434ec">3,256,514</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usdPerShare" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmQ5YTdmNDA4NDExYjQ0ZDU4NjM1YmViOWY0MTE2ZWUwL3RhYmxlcmFuZ2U6ZDlhN2Y0MDg0MTFiNDRkNTg2MzViZWI5ZjQxMTZlZTBfNi0zLTEtMS0w_6be4080b-dd21-45c5-9b9a-8c805c15ec74">4.87</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The weighted-average grant date fair value of options granted during the nine months ended September&#160;30, 2020 and 2019, was $<ix:nonFraction unitRef="usdPerShare" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTg0Ng_a060ffce-52ab-45d6-9ec6-dd9b6506b98e">6.17</ix:nonFraction> and $<ix:nonFraction unitRef="usdPerShare" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTg1Mw_933bff8c-e99e-4457-a6d8-f305a381023a">2.47</ix:nonFraction> per share, respectively.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Cash received from the exercise of stock options was $<ix:nonFraction unitRef="usd" contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:ProceedsFromStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTkzNA_0efdcef6-4e99-4183-91dc-c4768ada51f2">1,732</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" name="us-gaap:ProceedsFromStockOptionsExercised" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTk0MQ_34ec72a0-a2c9-4bd0-8256-796a86234eae">121</ix:nonFraction> for the nine months ended September&#160;30, 2020 and 2019, respectively.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Restricted stock units (RSUs)</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In July 2019, the Company issued RSUs with service conditions to employees. The awards cliff-vest <ix:nonNumeric contextRef="i21122848e22340a5b13c5314446b323a_D20190701-20190731" format="ixt-sec:durwordsen" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMjEyMQ_c938ab37-8774-4e02-ad4c-43a897739acc">two years</ix:nonNumeric> after the grant date. In January 2020, the Company issued <ix:nonFraction unitRef="shares" contextRef="ia8ca4eee9ada47b898379003caa54e1e_D20200101-20200131" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMjE4Mg_eaca97dc-876d-4616-9e9e-f00993f334a7">324,932</ix:nonFraction> RSUs with a service condition to employees for which the vesting term is annually over <ix:nonNumeric contextRef="ia8ca4eee9ada47b898379003caa54e1e_D20200101-20200131" format="ixt-sec:durwordsen" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMjI3Mg_0e39fee2-638a-4a9b-bc4d-c90766d7599b">four years</ix:nonNumeric>. Vesting of these awards is contingent on the fulfillment of the service conditions during the vesting term.</span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIwMQ_f1ddee9e-7e74-42af-b179-ad6806ab168c" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A summary of the RSU activity under the 2017 Plan is as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:97.275%"><tr><td style="width:1.0%"></td><td style="width:84.567%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:13.233%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Number of Shares</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested at January&#160;1, 2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="i838eb3d0288f44029b78208281fec02f_I20191231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjFmMTAzNjhlYTYyYjRkMjJhY2E2YTM2ZTkwNzVhYjdiL3RhYmxlcmFuZ2U6MWYxMDM2OGVhNjJiNGQyMmFjYTZhMzZlOTA3NWFiN2JfMS0xLTEtMS0w_9ca09287-4588-444e-9ea4-fb4df92035f2">447,336</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Granted</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="ie1372489078648cdba3441129be09f64_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjFmMTAzNjhlYTYyYjRkMjJhY2E2YTM2ZTkwNzVhYjdiL3RhYmxlcmFuZ2U6MWYxMDM2OGVhNjJiNGQyMmFjYTZhMzZlOTA3NWFiN2JfMi0xLTEtMS0w_4a3ea8d8-f54f-4056-9086-14640d0c0a98">324,932</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Vested</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="ie1372489078648cdba3441129be09f64_D20200101-20200930" decimals="INF" format="ixt:zerodash" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjFmMTAzNjhlYTYyYjRkMjJhY2E2YTM2ZTkwNzVhYjdiL3RhYmxlcmFuZ2U6MWYxMDM2OGVhNjJiNGQyMmFjYTZhMzZlOTA3NWFiN2JfMy0xLTEtMS0w_7d94a753-9119-48d4-b0c6-177633544dee">&#8212;</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Forfeited</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(<ix:nonFraction unitRef="shares" contextRef="ie1372489078648cdba3441129be09f64_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjFmMTAzNjhlYTYyYjRkMjJhY2E2YTM2ZTkwNzVhYjdiL3RhYmxlcmFuZ2U6MWYxMDM2OGVhNjJiNGQyMmFjYTZhMzZlOTA3NWFiN2JfNC0xLTEtMS0w_45a1ec1b-9b7d-49bb-95a1-dc37ede27ce1">31,406</ix:nonFraction>)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="shares" contextRef="id4ba0bd274ff44048102f9d2db62142f_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjFmMTAzNjhlYTYyYjRkMjJhY2E2YTM2ZTkwNzVhYjdiL3RhYmxlcmFuZ2U6MWYxMDM2OGVhNjJiNGQyMmFjYTZhMzZlOTA3NWFiN2JfNS0xLTEtMS0w_2c9183ff-635d-4282-b6a8-a457d9ca5eff">740,862</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Stock-based compensation expense</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company uses the provisions of ASC 718, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Stock Compensation</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, to account for all stock-based awards to employees and non-employees.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The measurement date for employee awards is generally the date of grant. Stock-based compensation expense is recognized over the requisite service period, which is generally the vesting period, using the straight-line method.</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">20</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><ix:continuation id="i077d72ed9d0d4092a22bf350e3640a50"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" 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style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.723%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span 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style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.723%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="9" 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i04488c638a744868abe938e6ca79a79d_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AllocatedShareBasedCompensationExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmE0YjU5NjkxODZhMzQzNzJhODY4NTA5OTFkMjU0MzU4L3RhYmxlcmFuZ2U6YTRiNTk2OTE4NmEzNDM3MmE4Njg1MDk5MWQyNTQzNThfMi03LTEtMS0w_ff986cc1-afb4-40c9-aee0-10d31f4d2345">1,636</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmE0YjU5NjkxODZhMzQzNzJhODY4NTA5OTFkMjU0MzU4L3RhYmxlcmFuZ2U6YTRiNTk2OTE4NmEzNDM3MmE4Njg1MDk5MWQyNTQzNThfMy01LTEtMS0w_81e3b0ca-4cd2-426d-8a15-65d0c9537375">2,629</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="icbd44dae89854fc2b72b803f8e899d37_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AllocatedShareBasedCompensationExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmE0YjU5NjkxODZhMzQzNzJhODY4NTA5OTFkMjU0MzU4L3RhYmxlcmFuZ2U6YTRiNTk2OTE4NmEzNDM3MmE4Njg1MDk5MWQyNTQzNThfMy03LTEtMS0w_9ad0f0c7-8575-428a-9035-ce11125231f0">1,974</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock-based compensation expense included in Total operating expenses</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times 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#000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AllocatedShareBasedCompensationExpense" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOmE0YjU5NjkxODZhMzQzNzJhODY4NTA5OTFkMjU0MzU4L3RhYmxlcmFuZ2U6YTRiNTk2OTE4NmEzNDM3MmE4Njg1MDk5MWQyNTQzNThfNC0zLTEtMS0w_1a3fd60e-1dc9-4f16-9c74-57522a3a85c2">1,285</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid 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style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:AllocatedShareBasedCompensationExpense" scale="3" 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name="us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMzIwOQ_f57c671a-f9cc-462c-93fa-e095525d38e5">15,007</ix:nonFraction> and $<ix:nonFraction unitRef="usd" contextRef="id4ba0bd274ff44048102f9d2db62142f_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMzIxNg_fe160877-88ca-44e6-98f2-e79940dbad38">2,269</ix:nonFraction> of 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMzQwNA_9ebc6a84-4cbb-4a9e-88fb-5e7261d18eb6">2.6</ix:nonNumeric> years, respectively.</span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIxMA_be962a2b-8e1e-49a7-8e79-c9669e4dc791" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The fair value of each option award is 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style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Risk-free interest rate</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="number" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="3" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjJhN2Y1ZWE0MDEzNTRhNzdhNzAwYTc4YTUwMjg5YTIwL3RhYmxlcmFuZ2U6MmE3ZjVlYTQwMTM1NGE3N2E3MDBhNzhhNTAyODlhMjBfMi0xLTEtMS0w_0895e8c3-07cc-471c-97d1-eeb77dabedb1">0.4</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="number" contextRef="i03ae810a048042c693b2af5609713bb1_D20190701-20190930" decimals="3" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" scale="-2" 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected dividend yield</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="number" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="INF" format="ixt:zerodash" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" scale="-2" 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="number" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="INF" format="ixt:zerodash" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjJhN2Y1ZWE0MDEzNTRhNzdhNzAwYTc4YTUwMjg5YTIwL3RhYmxlcmFuZ2U6MmE3ZjVlYTQwMTM1NGE3N2E3MDBhNzhhNTAyODlhMjBfMy03LTEtMS0w_a52a36d1-3f22-4419-bcf8-4f504b1f4a86">&#8212;</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected term (years)</span></td><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonNumeric contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" format="ixt-sec:duryear" name="us-gaap:SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" 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1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="number" contextRef="id705221f53a54311a556634abbb20b22_D20190101-20190930" decimals="2" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" scale="-2" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjJhN2Y1ZWE0MDEzNTRhNzdhNzAwYTc4YTUwMjg5YTIwL3RhYmxlcmFuZ2U6MmE3ZjVlYTQwMTM1NGE3N2E3MDBhNzhhNTAyODlhMjBfNS03LTEtMS0w_4c16cbd5-c03a-4098-b3e0-b2700ff9a257">74</ix:nonFraction>&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr></table></div></ix:nonNumeric><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Employee Stock Purchase Plan</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the year ended December 31, 2017, the Board adopted, and the Company&#8217;s stockholders approved the 2017 employee stock purchase plan (the 2017 ESPP). The Company initially reserved <ix:nonFraction unitRef="shares" contextRef="i8f51005d200e4cdfa302759bb7ba89f7_I20171231" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:CommonStockCapitalSharesReservedForFutureIssuance" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMzgwMw_285f21c8-70dd-4279-a2c1-122cd7a926bf">225,000</ix:nonFraction> shares of common stock for issuance under the 2017 ESPP. In January 2020, the number of shares of common stock for issuance under the 2017 ESPP was increased by <ix:nonFraction unitRef="shares" contextRef="i6fd456c2d42c400ea4d38be0c4a1456a_D20200101-20200131" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMzk2Nw_ab4b4d45-3783-496a-98e7-eb79cf07388e">450,000</ix:nonFraction> shares. For the nine months ended September&#160;30, 2020 and 2019, the Company issued <ix:nonFraction unitRef="shares" contextRef="i33ef901aaf7847cdadd9512f2d407bbd_D20200101-20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDA2Ng_87b82941-b0d5-4186-93b8-537979916da6">68,419</ix:nonFraction> and <ix:nonFraction unitRef="shares" contextRef="iaea4619f3e224560a98b01b7d2e6b176_D20190101-20190930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDA4Mg_6a394700-052f-4eee-a65a-216c2e75906f">82,281</ix:nonFraction>, respectively, shares under the 2017 ESPP. The Company did <ix:nonFraction unitRef="shares" contextRef="i91048226f5964c23852173195585bbc2_D20200701-20200930" decimals="INF" format="ixt-sec:numwordsen" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTA5OTUxMTYzNzIzOA_525bf980-03d8-4071-94e7-781b7c55e4a1"><ix:nonFraction unitRef="shares" contextRef="ic9311c8534834197830870feabcc248f_D20190701-20190930" decimals="INF" format="ixt-sec:numwordsen" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfMTA5OTUxMTYzNzIzOA_a8ba1510-ebb7-434c-af0c-4e1b79734954">no</ix:nonFraction></ix:nonFraction>t issue any shares under the 2017 ESPP for the three months ended September&#160;30, 2020 and 2019. As of September&#160;30, 2020, there were <ix:nonFraction unitRef="shares" contextRef="i30ccb621b14b4652a0e3860d79b2b429_I20200930" decimals="INF" format="ixt:numdotdecimal" name="us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDE0OQ_a7223cb3-b1bb-4d1f-b61b-4d0b61a22237">656,666</ix:nonFraction> shares available for issuance under the 2017 ESPP.</span></div></ix:continuation><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">21</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_73"></div><hr style="page-break-after:always"/><div style="min-height:90pt;width:100%"><div style="margin-bottom:6pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Mersana Therapeutics,&#160;Inc.</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Notes to condensed consolidated financial statements (continued)</span></div><div style="text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(in thousands, except share and per share data)</span></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">(unaudited)</span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">10.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:LesseeFinanceLeasesTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjA4Nw_dabdc741-6d05-48cf-ba21-3411ff2cecc8" continuedAt="ic718d815b992497d810921a5eab18149" escape="true"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:LesseeOperatingLeasesTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjA4Nw_e969e5c3-872f-4df9-9820-75c76828a237" continuedAt="iea335e84ee6343408757347d075bba7a" escape="true">Leases</ix:nonNumeric></ix:nonNumeric></span></div><ix:continuation id="ic718d815b992497d810921a5eab18149"><ix:continuation id="iea335e84ee6343408757347d075bba7a"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company has an operating lease for its office space in Cambridge, MA and operating and finance leases for certain equipment. In March 2020, the Company entered into the Seventh Amendment to the office space lease to extend the term of the lease through March 2026 and to provide the Company with a tenant improvement allowance of $<ix:nonFraction unitRef="usd" contextRef="i1fe02605837640f29e6e37e47436bce0_D20200301-20200331" decimals="-3" name="mrsn:TenantImprovementAllowance" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMzUw_09c649ca-ab08-448e-991a-3b65f2c3df0f">172</ix:nonFraction>. The current rate per square foot that is in place through March 2021 (the original expiration date of the lease) did not change. After March 2021, there are predetermined fixed escalations of the rate as outlined in the amendment. The Company has an option to extend the lease term for an additional <ix:nonNumeric contextRef="i0d5c81cb160646be842b64a016fa2fbe_I20200930" format="ixt-sec:durwordsen" name="us-gaap:LesseeOperatingLeaseRenewalTerm" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfNjU0_612579e7-d245-478f-bb4e-8eba36320fe1">five years</ix:nonNumeric>. The Company&#8217;s exercise of this option was not considered reasonably certain as of September&#160;30, 2020. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The extension is accounted for as a lease modification. The Company assessed the lease classification of the amended office space lease at the modification date and determined that the amended office space lease should be accounted for as an operating lease. The right-of-use asset and corresponding operating lease liability have been remeasured based on the present value of remaining lease payments over the remaining extended lease term, using the incremental borrowing rate applicable as of the lease modification date. The Company determined the appropriate incremental borrowing rate by using a synthetic credit rating which was estimated based on an analysis of outstanding debt of companies with similar credit and financial profiles. Since the operating lease is a net lease, as the non-lease components (i.e., common area maintenance) are paid separately from rent based on actual costs incurred, such non-lease components were not included in the right-of-use asset and liability and are reflected as an expense in the period incurred. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As a result of the modification in March 2020, the Company recorded an increase of $<ix:nonFraction unitRef="usd" contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331" decimals="-3" format="ixt:numdotdecimal" name="mrsn:LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMTg3Ng_17bf2ad7-0e0d-43c4-92e6-a47d8c390cf8"><ix:nonFraction unitRef="usd" contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331" decimals="-3" format="ixt:numdotdecimal" name="mrsn:LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMTg3Ng_bd987a7e-2949-49b0-bab4-6f34c352584d">9,980</ix:nonFraction></ix:nonFraction> to its right-of-use (ROU) asset and lease liabilities in the first quarter of 2020.</span></div><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:FinanceLeaseLiabilityMaturityTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjE5OTAyMzI1NzY0Ng_0706a074-5ea1-4f27-8d39-6f53ebc1109e" escape="true"><ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:LesseeOperatingLeaseLiabilityMaturityTableTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjE5OTAyMzI1NzY0Ng_64854a8f-d1fe-4981-8ee9-a0c68003bb38" escape="true"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Operating leases</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Finance leases</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMS0xLTEtMS0w_1ee253ab-d130-4f87-b93f-fb5743df7556">604</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMS0zLTEtMS0w_0b6891c8-83e7-4b5c-aaac-e37a27985f6c">29</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 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id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMi0zLTEtMS0w_5888f8c9-55f3-4989-b431-1f4ce2eaa313">116</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMy0xLTEtMS0w_91e73390-fd58-45dc-b0b3-378c66e07454">2,843</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:FinanceLeaseLiabilityPaymentsDueYearTwo" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMy0zLTEtMS0w_55849542-68c6-487a-9602-a25898ea528b">84</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfNC0xLTEtMS0w_55f12560-e130-4b47-9150-27472dc63c4c">2,928</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="us-gaap:FinanceLeaseLiabilityPaymentsDueYearThree" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfNC0zLTEtMS0w_9ed05093-a0a5-4f6e-b3d1-92517d43cb14">74</ix:nonFraction>&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024 and thereafter</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="mrsn:LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfNS0xLTEtMS0w_ca7b7606-8f07-4f3e-814c-b224c77546f4">6,904</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" name="mrsn:FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" scale="3" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfNS0zLTEtMS0w_beaa5393-8551-408b-ace9-716a1d03da29">18</ix:nonFraction>&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total lease payments</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"><ix:nonFraction unitRef="usd" contextRef="i2747742065f74d22a950e115eb8eb517_I20200930" decimals="-3" format="ixt:numdotdecimal" name="us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue" scale="3" 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style="margin-bottom:12pt"><span><br/></span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_76"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">11.&#160;<ix:nonNumeric contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930" name="us-gaap:CommitmentsDisclosureTextBlock" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83Ni9mcmFnOmRjZDQ4N2Y3MThmMjRjNTU4ODQzYWQyNDY2ZmI0NWM3L3RleHRyZWdpb246ZGNkNDg3ZjcxOGYyNGM1NTg4NDNhZDI0NjZmYjQ1YzdfNjAx_91126555-a465-42fa-8a02-2137395c9cdb" continuedAt="i8a382c110e744f9ab21e800316f897cb" escape="true">Commitments</ix:nonNumeric></span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"><ix:continuation id="i8a382c110e744f9ab21e800316f897cb" continuedAt="i54077df528dc4a9093dde16a6113d420">License agreements</ix:continuation></span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"><ix:continuation id="i54077df528dc4a9093dde16a6113d420">Through September&#160;30, 2020, the Company had licensed intellectual property from <ix:nonFraction unitRef="company" contextRef="i50c726538a884e8a86a9ae5377e20db5_D20200101-20200930" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83Ni9mcmFnOmRjZDQ4N2Y3MThmMjRjNTU4ODQzYWQyNDY2ZmI0NWM3L3RleHRyZWdpb246ZGNkNDg3ZjcxOGYyNGM1NTg4NDNhZDI0NjZmYjQ1YzdfMTA0_8a35aeb2-cc23-40ab-8d09-5bfc487d5b6a">three</ix:nonFraction> biotechnology companies. 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The Company did <ix:nonFraction unitRef="usd" contextRef="i6c5f0c59106a46479c0a0cd699857d1a_D20200701-20200930" decimals="INF" format="ixt-sec:numwordsen" name="mrsn:MilestonePayment" scale="0" id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83Ni9mcmFnOmRjZDQ4N2Y3MThmMjRjNTU4ODQzYWQyNDY2ZmI0NWM3L3RleHRyZWdpb246ZGNkNDg3ZjcxOGYyNGM1NTg4NDNhZDI0NjZmYjQ1YzdfMjE5OTAyMzI1NzIxMA_126cde54-7e5c-4832-ace1-a87d4677ae83">no</ix:nonFraction>t record any milestone payments during the three months ended September 30, 2020.</ix:continuation> </span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">22</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_82"></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;2.&#160;Management&#8217;s Discussion and Analysis of Financial Condition and Results of Operations</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited condensed consolidated financial statements and the accompanying notes appearing elsewhere in this Quarterly Report on Form 10-Q and the audited financial statements and the accompanying notes included in our Annual Report on Form 10-K for the year ended December 31, 2019 filed with the Securities and Exchange Commission (SEC) on February 28, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Our actual results and the timing of certain events may differ materially from the results discussed, projected, anticipated, or indicated in any forward-looking statements. We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Quarterly Report. In addition, even if our results of operations, financial condition and liquidity, and the development of the industry in which we operate are consistent with the forward-looking statements contained in this Quarterly Report, they may not be predictive of results or developments in future periods. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">The following information and any forward-looking statements should be considered in light of factors discussed elsewhere in this Quarterly Report on Form 10-Q, in our Annual Report on Form 10-K for the year ended December 31, 2019, filed with the SEC on February 28, 2020, and in our Quarterly Report on Form 10-Q for the quarterly period ending March 31, 2020, filed with the SEC on May 8, 2020, including those risks identified under Item 1A. Risk Factors.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">We caution readers not to place undue reliance on any forward-looking statements made by us, which speak only as of the date they are made. We disclaim any obligation, except as specifically required by law and the rules of the SEC, to publicly update or revise any such statements to reflect any change in our expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Overview</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We are a clinical-stage biopharmaceutical company focused on developing antibody drug conjugates, or ADCs, that offer a clinically meaningful benefit for cancer patients with significant unmet need. We have leveraged 20 years of industry learning in the ADC field to develop proprietary and differentiated technology platforms that enable us to design ADCs to have improved efficacy, safety and tolerability relative to existing ADC therapies.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We believe that our innovative platforms which include Dolaflexin and Dolasynthen, each delivering our DolaLock payload, as well as Immunosynthen, delivering a novel stimulator of interferon genes, or STING, agonist, provide a highly-efficient product engine that has enabled a robust discovery pipeline for us and our partners. Our ADCs in preclinical and clinical studies are first-in-class molecules that target multiple tumor types with high unmet medical need and have exhibited improved safety and efficacy compared to ADCs developed using first-generation technology.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our goal is to become a leading oncology company by leveraging the potential of our innovative and differentiated ADC technologies and the experience and competencies of our management team to identify, acquire and develop promising ADC product candidates and to commercialize cancer therapeutics that are improvements over existing treatments.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">XMT-1536, a first-in-class ADC targeting the sodium-dependent phosphate transport protein NaPi2b, utilizes the Dolaflexin platform to deliver an average of 10 to 12 auristatin DolaLock payload molecules per antibody. The NaPi2b antigen is broadly expressed in non-small cell lung cancer, or NSCLC, adenocarcinoma and ovarian cancer with limited expression in normal tissue. We are actively recruiting and dosing patients with ovarian cancer and NSCLC adenocarcinoma, where a majority of patients express NaPi2b, in a Phase 1 clinical trial.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">23</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We have also selected our next clinical product candidate, XMT-1592. XMT-1592 uses one of our new platforms, Dolasynthen, and also targets NaPi2b. XMT-1592 comprises the same proprietary NaPi2b antibody and potent auristatin DolaLock payload with controlled bystander effect as XMT-1536, with the additional features of homogeneous, site-specific bioconjugation and precise drug-to-antibody ratio, or DAR. We filed an Investigational New Drug (IND) application in the first quarter of 2020 and initiated the Phase 1 dose escalation study of XMT-1592 in the second quarter of 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our early-stage programs include a potentially first-in-class B7-H4-targeted DolaLock ADC. Our objective is to rapidly progress through IND-enabling studies and scale up manufacturing activities with third parties. B7-H4 provides significant opportunities for development in areas of high unmet need such as breast cancer, NSCLC and ovarian cancer.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In addition, we have established strategic research and development partnerships with Merck KGaA and Asana Biosciences for the development and commercialization of additional ADC product candidates against a limited number of targets selected by our partners based on our Fleximer platform. We believe the potential of our ADC technologies, supported by our world-class management team and protected by our robust intellectual property portfolio, will allow us to develop targeted and highly tailored therapies to help cancer patients become cancer survivors.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Since inception, our operations have focused on such matters as building our platforms, identifying potential product candidates, producing drug substance and drug product material for use in preclinical studies, conducting preclinical and toxicology studies, manufacturing clinical study material and conducting clinical studies, establishing and protecting our intellectual property, staffing our company and raising capital. We do not have any products approved for sale and have not generated any revenue from product sales. We have funded our operations primarily through our strategic partnerships, private placements of our convertible preferred stock and public offerings of our common stock. In April 2020, we sold approximately 10.9 million shares of common stock and received net proceeds of $63.0 million. In addition, in June 2020, we sold 9.2 million shares of common stock and received net proceeds of $164.0 million.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Since inception, we have incurred significant cumulative operating losses. For the nine months ended September&#160;30, 2020, the net loss was $59.2 million, compared to net loss of $12.0 million in the nine months ended September&#160;30, 2019. The difference year over year is primarily attributable to $40.0 million in revenue that was recognized in the first quarter of 2019 as a result of the discontinuation of the partnership with Takeda in that quarter. As of September&#160;30, 2020, we had an accumulated deficit of $251.6 million. We expect to continue to incur significant expenses and operating losses over the next several years. We anticipate that our expenses will increase significantly in connection with our ongoing activities, as we:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">continue clinical development activities for our lead product candidates XMT-1536 and XMT-1592;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">develop a research assay and companion diagnostic for the NaPi2b biomarker;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">continue activities to discover, validate and develop additional product candidates;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">maintain, expand and protect our intellectual property portfolio; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">hire additional research, development and general and administrative personnel.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Impact of COVID-19 on Our Business</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We are continuing to monitor the impact of the COVID-19 pandemic on our operations and ongoing clinical and preclinical development, as well as discovery efforts. Mitigation activities to minimize COVID-19-related operation disruptions are ongoing and include:</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">24</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">In line with guidance from the U.S. Centers for Disease Control and Prevention (CDC) and the Commonwealth of Massachusetts, we have implemented work from home measures for all non-laboratory employees and have suspended all business travel. We have also prioritized laboratory activities and implemented staggered schedules in the interest of safety and efficiency for laboratory-based employees. We will continue to modify and adapt our measures to align with guidance as the pandemic evolves.</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">We are currently enrolling patients at investigational sites in different geographic areas across the United States, Canada and Australia in the XMT-1536 Phase 1 study and within the United States in the XMT-1592 Phase 1 dose escalation study. We are in the process of initiating additional clinical sites both inside and outside the United States to increase enrollment, which could additionally mitigate potential regional impacts from COVID-19. Consistent with FDA guidance, we issued an administrative letter to allow for remote patient monitoring and remote testing, when possible. </span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">To the best of our knowledge, our contract manufacturing partners continue to operate their manufacturing facilities at or near normal levels, and we have not experienced any COVID-related delays in our manufacturing to date. We believe we have sufficient inventory of XMT-1536 and XMT-1592 to support our ongoing clinical studies. We have planned manufacturing runs to address all currently anticipated future needs. At this time, and subject to further COVID-19 implications, we do not anticipate any disruptions to our clinical supply.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The ultimate impact of the coronavirus pandemic on our business operations is highly uncertain and subject to change and will depend on future developments, which cannot be accurately predicted. While the pandemic did not materially affect our financial results and business operations in the third quarter ended September 30, 2020, we are unable to predict the impact that COVID-19 will have on our financial position and operating results in future periods due to numerous uncertainties. Management is actively monitoring this situation and the possible effects on our financial condition, operations, suppliers, industry, and our employees. For additional information about risks and uncertainties related to the COVID-19 pandemic that may impact our business, our financial condition or our results of operations, see &#8220;Part II, Item 1A&#8212;Risk Factors&#8221; below in the Company&#8217;s Quarterly Report on Form 10-Q for the quarter ended March 31, 2020, filed on May 8, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Financial operations overview</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Revenue</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">To date, we have not generated any revenue from the sale of products. All of our revenue has been generated from strategic partnerships.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2014, we entered into an agreement with Merck KGaA for the development and commercialization of ADC product candidates utilizing Fleximer for up to six target antigens. Merck KGaA is responsible for generating antibodies against the target antigens and we are responsible for generating Fleximer and our proprietary payloads and conjugating this to the antibody to create the ADC product candidates. Merck KGaA has the exclusive right to and is responsible for the further development and commercialization of these ADC product candidates. In May 2018, we entered into a supply agreement with Merck KGaA for the supply of materials that could be used for IND-enabling studies and clinical trials.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For the three months ended September&#160;30, 2020 we recognized an immaterial amount of revenue related to the Merck KGaA Agreements. For the nine months ended September&#160;30, 2020 we recognized revenue of $0.8 million and for the three and nine months ended September&#160;30, 2019, we recognized $0.8 million and $2.1 million, respectively, of revenue related to the Merck KGaA agreements.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In January 2016, we entered into collaboration agreements with Takeda for the development and commercialization of XMT-1522, a HER2-targeted ADC, and up to seven ADC product candidates utilizing Fleximer. Our collaboration agreements with Takeda were terminated during the first quarter of 2019. We recognized the </span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">25</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">remaining deferred revenue of $40.0 million related to the termination of the Takeda agreements in the first quarter of 2019. We do not expect to have any further revenue related to these agreements.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We have provided limited services to Asana BioSciences. For the three and nine months ended September&#160;30, 2019 we recorded an immaterial amount of revenue related to these services. We did not record any revenue related to these services in the three and nine months ended September&#160;30, 2020.  </span></div><div style="margin-bottom:12pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For the foreseeable future, we expect substantially all of our revenue to be generated from our collaboration agreements with Merck KGaA and Asana BioSciences. Given the uncertain nature and timing of clinical development, we cannot predict when or whether we will receive further milestone payments or any royalty payments under these collaborations.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Operating expenses</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Research and development expenses</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Research and development expenses consist primarily of costs incurred for our research and development activities, including our drug discovery efforts, and the development of our product candidates, which include:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">employee-related expenses, including salaries, bonuses, benefits and stock-based compensation expense;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">costs of funding research and development performed by third parties that conduct research, preclinical activities, manufacturing and clinical trials on our behalf;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">laboratory supplies;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">facility costs, including rent, depreciation and maintenance expenses; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">upfront and milestone payments under our third-party licensing agreements.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Research and development costs are expensed as incurred. Costs of certain activities, such as manufacturing and preclinical and clinical studies, are generally recognized based on an evaluation of the progress to completion of specific tasks. Costs for certain development activities, such as clinical studies, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations and information provided to us by the third parties with whom we contract.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials and manufacturing costs. We expect that our total future research and development costs will continue to increase over current levels, depending on the progress of our clinical development programs. There are numerous factors associated with the successful development and commercialization of any of our product candidates, including future trial design and various regulatory requirements, many of which cannot be determined with accuracy at our current stage of development. Additionally, future commercial and regulatory factors beyond our control may impact our clinical development programs and plans.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A significant portion of our research and development costs have been external costs, which we track on a program-by-program basis following nomination as a product candidate. We have not historically tracked all of our internal research and development expenses on a </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">program-by-program basis as they are deployed across multiple projects under development. The following table summarizes our external research and development expenses, by program, following nomination as a development candidate for the three and nine months ended </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2020 and 2019</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. All external research and development expenses not attributable to the XMT-1536, XMT-1592 and XMT-1522 programs are captured within preclinical and discovery costs. These costs relate to XMT-1592 prior to its designation in early 2020 as our next ADC clinical candidate, as well as additional earlier discovery stage </span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">26</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">programs and certain unallocated costs. We terminated the development of XMT-1522 in the first quarter of 2019. </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our internal research and development costs are primarily personnel-related costs, stock-based compensation costs, and facility costs, including depreciation, and lab consumables. </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:45.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.720%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:11.723%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(in&#160;thousands)</span></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">XMT-1536 external costs</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,451&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,193&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">10,356&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,801&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">XMT-1592 external costs</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,149&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,994&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;border-right:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">XMT-1522 external costs</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">305&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,267&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Preclinical and discovery costs</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,348&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,994&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,878&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,383&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Internal research and development costs</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7,598&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,209&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">21,951&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">20,159&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total research and development costs</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,546&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,701&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">44,179&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="padding:0 1pt"></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">42,610&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The successful development of our product candidates is highly uncertain. As such, we cannot reasonably estimate or know the nature, timing and estimated costs of the efforts that will be necessary to complete the remainder of the development of our product candidates. We are also unable to predict when, if ever, material net cash inflows will commence from the development efforts associated with our product candidates. This is due to the numerous risks and uncertainties associated with developing drugs, including the uncertainty of:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">successful completion of preclinical studies and IND-enabling studies;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">successful enrollment in and completion of clinical trials;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">receipt of marketing approvals from applicable regulatory authorities;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">establishing commercial manufacturing capabilities or making arrangements with third-party manufacturers;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">obtaining and maintaining patent and trade secret protection and regulatory exclusivity for our product candidates;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">commercializing the product candidates, if and when approved, whether alone or in collaboration with others; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">continued acceptable safety profile of the drugs following approval.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A change in the outcome of any of these or other variables with respect to the development, manufacture or commercialization of any of our product candidates would significantly change the costs, timing and viability associated with the development of that product candidate.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">General and administrative expenses</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">General and administrative expenses consist primarily of salaries and other employee-related costs, including stock-based compensation, for personnel in executive, finance, accounting, business development, legal operations, information technology and human resources functions. Other significant costs include facility costs not otherwise included in research and development expenses, legal and other fees relating to patent and corporate matters, and fees for accounting and consulting services.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We anticipate that our general and administrative expenses will increase in the future to support continued research and development activities, including increased costs related to the hiring of additional personnel, fees to outside consultants and patent costs, among other expenses.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">27</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Other income (expense)</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Other income (expense) consists primarily of interest income earned on cash equivalents and marketable securities. Interest expense is related to borrowings under the credit facility that we entered into in May 2019 and amended in August 2020. These borrowings bear a floating per annum rate interest, as well as a final payment of 5.5% of the amounts drawn, that is being recorded as interest expense over the term through the maturity date using the effective-interest method. Also included in interest expense is the amortization of the deferred financing costs and the accretion of debt discount relating to the credit facility.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Results of Operations</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Comparison of the three months ended September&#160;30, 2020 and 2019</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table summarizes our results of operations for the three months ended September&#160;30, 2020 and 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:55.470%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.844%"></td><td style="width:0.1%"></td></tr><tr style="height:21pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Dollar&#160;Change</span></td></tr><tr style="height:12pt"><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(in thousands)</span></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Collaboration revenue</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">844&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(833)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Operating expenses:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Research and development</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,546&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,701&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,845&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">General and administrative</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,881&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,436&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,445&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total operating expenses</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">22,427&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">18,137&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,290&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other income (expense):</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Interest income</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">19&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">608&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(589)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Interest expense</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(92)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(107)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">15&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total other income (expense), net</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(73)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">501&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(574)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net loss</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(22,489)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(16,792)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(5,697)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Collaboration Revenue</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Collaboration revenue was immaterial during the three months ended September&#160;30, 2020 and $0.8 million during the three months ended September&#160;30, 2019. The decrease in collaboration revenue was primarily a result of the completion of research services associated with a target included in the Merck KGaA Agreement during the three months ended September&#160;30, 2019.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Research and Development Expense</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Research and development expense increased by $2.8 million from $13.7 million for the three months ended September&#160;30, 2019 to $16.5 million for the three months ended September&#160;30, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The increase in research and development expense was primarily attributable to the following:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $2.7 million related to manufacturing, clinical and regulatory activities for XMT-1536;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $1.1 million related to employee compensation, primarily due to increased headcount supporting the growth of our research and development activities, and the increase in valuation of stock-based awards granted to employees, resulting in higher stock-based compensation expense;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.5 million related to manufacturing activities for our discovery stage programs;</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">28</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.4 million related to XMT-1592 clinical expenses;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.4 million related to consulting and professional fees; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.2 million related to advancement of companion diagnostic development efforts for the NaPi2B biomarker. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">These increased costs were partially offset by the following:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">a decrease of $2.3 million related to preclinical development and manufacturing activities for XMT-1592; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">a decrease of $0.2 million related to the development and manufacturing activities for XMT-1522.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We expect our research and development expenses to increase as we continue our clinical development of XMT-1536 and XMT-1592 and continue to advance our preclinical product candidate pipeline and invest in improvements in our ADC technologies.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">General and Administrative Expense</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">General and administrative expense increased by $1.4 million from $4.4 million during the three months ended September&#160;30, 2019 to $5.9 million during the three months ended September&#160;30, 2020. The increase in general and administrative expense was primarily attributable to the following:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.9 million related to consulting and professional fees;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.3 million related to employee compensation, primarily due to the increase in valuation of stock-based awards granted to employees, resulting in higher stock-based compensation expense; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.2 million in facility-related costs as a result of the amendment of our lease in March 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We expect that our general and administrative expense will increase in future periods as we expand our operations. These increases will likely include legal, auditing and filing fees, additional insurance premiums and general compliance and consulting expenses.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Total Other Income (Expense), net</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Total other income (expense), net was $0.1 million and $0.5 million for the three months ended September&#160;30, 2020 and 2019, respectively. Other income consists primarily of interest income on cash equivalents and short-term marketable securities. Interest expense related to our outstanding borrowings under the credit facility.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">29</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Comparison of the nine months ended September&#160;30, 2020 and 2019</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table summarizes our results of operations for the nine months ended September&#160;30, 2020 and 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:55.470%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.844%"></td><td style="width:0.1%"></td></tr><tr style="height:21pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" rowspan="2" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Dollar&#160;Change</span></td></tr><tr style="height:12pt"><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(in thousands)</span></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Collaboration revenue</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">817&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">42,081&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(41,264)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Operating expenses:</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Research and development</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">44,179&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">42,610&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,569&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">General and administrative</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">15,988&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,072&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,916&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total operating expenses</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">60,167&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">55,682&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,485&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Other income (expense):</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Interest income</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">414&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,785&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(1,371)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Interest expense</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(267)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(146)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(121)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total other income (expense), net</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">147&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,639&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(1,492)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net income (loss)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(59,203)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(11,962)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(47,241)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Collaboration Revenue</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Collaboration revenue was $0.8 million during the nine months ended September&#160;30, 2020 and $42.1 million during the nine months ended September&#160;30, 2019. The decrease in collaboration revenue was primarily a result of the termination of the Takeda agreements and the recognition of the remaining deferred revenue of $40.0 million in the first quarter of 2019. During the nine months ended September&#160;30, 2020 revenue of $0.8 million was recognized as a result of completion of research services associated with a target included in the Merck KGaA Agreement. Additionally, during the nine months ended September&#160;30, 2019, collaboration revenue of $1.0 million was recognized related to the Merck KGaA Agreement and Merck KGaA Supply Agreement.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Research and Development Expense</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Research and development expense increased by $1.6 million from $42.6 million for the nine months ended September&#160;30, 2019 to $44.2 million for the nine months ended September&#160;30, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The increase in research and development expense was primarily attributable to the following:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $3.7 million related to manufacturing, clinical and regulatory activities for XMT-1536;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $1.8 million related to employee compensation, primarily due to increased headcount supporting the growth of our research and development activities, and the increase in valuation of stock-based awards granted to employees, resulting in higher stock-based compensation expense;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $1.3 million related to XMT-1592 clinical and regulatory expenses;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.8 million related to consulting and professional fees;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.7 million related to advancement of companion diagnostic development efforts for the NaPi2B biomarker;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.6 million related to manufacturing activities for our discovery stage programs; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.4 million related to a milestones paid for in-licensed technologies.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">30</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">These increased costs were partially offset by the following:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">a decrease of $4.8 million related to preclinical development and manufacturing activities for XMT-1592;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">a decrease of $2.0 million related to the development and manufacturing activities for XMT-1522; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">a decrease of $0.9 million to support partner programs.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We expect our research and development expenses to increase as we continue our clinical development of XMT-1536 and XMT-1592 and continue to advance our preclinical product candidate pipeline and invest in improvements in our ADC technologies.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">General and Administrative Expense</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">General and administrative expense increased by $2.9 million from $13.1 million during the nine months ended September&#160;30, 2019 to $16.0 million during the nine months ended September&#160;30, 2020. The increase in general and administrative was primarily attributable to the following:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $1.6 million related to consulting and professional fees;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $1.0 million related to employee compensation, primarily due to the increase in valuation of stock-based awards granted to employees, resulting in higher stock-based compensation expense; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">an increase of $0.3 million in facility-related costs as a result of the amendment of our lease in March 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We expect that our general and administrative expense will increase in future periods as we expand our operations. These increases will likely include legal, auditing and filing fees, additional insurance premiums and general compliance and consulting expenses.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Total Other Income (Expense), net</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Total other income (expense), net was $0.1 million and $1.6 million for the nine months ended September&#160;30, 2020 and 2019, respectively. Other income consists primarily of interest income on cash equivalents and short-term marketable securities. Interest expense was related to our outstanding borrowings under the credit facility.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Liquidity and Capital Resources </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Sources of Liquidity</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Since our initial public offering in July 2017, we have financed our operations primarily with the proceeds from our initial public offering, our follow-on public offerings and use of our at-the-market, or ATM, equity offering program established in July 2018. We completed a follow-on public offering on March 5, 2019 that resulted in net proceeds of $92.2 million. On May 8, 2019, we entered into a term-loan agreement which was subsequently amended on August 28, 2020. Pursuant to the amendment, we may be subject to certain conditions, borrow term loans in an aggregate amount of up to $30.0 million, of which $5.2 million were funded</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> upon execution of the amendment. These proceeds were used to repay the existing balance and satisfy our existing obligations to Silicon Valley Bank, or SVB. No additional amounts have been drawn since the initial draw of $5.2 million.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In April 2020, we sold approximately 10.9 million shares of common stock and received net proceeds of $63.0 million pursuant to our 2018 ATM. In addition, in June 2020, we sold 9.2 million shares of common stock in a follow-on offering and received net proceeds of approximately $164.0 million.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We terminated the 2018 ATM on April 9, 2020. On May 8, 2020, we established a new ATM pursuant to which we are able to sell $100.0 million of our common stock from time to time at prevailing market prices, or the 2020 ATM. </span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">31</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, we had not sold any shares under the 2020 ATM and had $100.0 million of availability under the program.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, we had cash and cash equivalents of $270.9 million.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Cash Flows</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table provides information regarding our cash flows for the nine months ended September&#160;30, 2020 and 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:70.214%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.842%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:0.601%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:12.843%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(in thousands)</span></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net cash used in operating activities</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(57,377)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000;padding:0 1pt"></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(55,168)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net cash provided by (used in) investing activities</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,215&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(43,793)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net cash provided by financing activities</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">228,747&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">97,473&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Increase (decrease) in cash, cash equivalents and restricted cash</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">208,585&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(1,488)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"></td></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Net Cash Used in Operating Activities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Net cash used in operating activities was $57.4 million for the nine months ended September&#160;30, 2020 and primarily consisted of a net loss of $59.2 million adjusted for changes in our net working capital and other non-cash items including stock-based compensation of $5.2 million and depreciation of $0.8 million. Net cash used in operating activities was $55.2 million for the nine months ended September&#160;30, 2019 and primarily consisted of a net loss of $12.0 million adjusted for non-cash items including the decrease in deferred revenue of $41.6 million primarily related to the Takeda agreements, stock-based compensation of $3.6 million and depreciation of $1.0 million, as well as change in our net working capital.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Net Cash Provided by (Used in) Investing Activities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Net cash provided by investing activities was $37.2 million during the nine months ended September&#160;30, 2020 and consisted primarily of maturities of marketable securities. Net cash used in investing activity was $43.8 million during the nine months ended September&#160;30, 2019 and consisted primarily of purchases of marketable securities, slightly offset by the maturity of marketable securities.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Net Cash Provided by Financing Activities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Net cash provided by financing activities was $228.7 million during the nine months ended September&#160;30, 2020 as compared to net cash provided by financing activities of $97.5 million during the nine months ended September&#160;30, 2019. During the nine months ended September&#160;30, 2020 cash provided by financing activities consisted primarily of $164.0 million related to the follow-on public offering in May 2020 and the proceeds from the use of the ATM of $63.0 million in April 2020 as well as proceeds from exercise of stock options of $1.7 million, offset by the payment of $0.2 million of debt. During the nine months ended September&#160;30, 2019 cash provided by financing activities consisted primarily of the proceeds from our follow-on public offering.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Funding Requirements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We expect our cash expenditures to increase in connection with our ongoing activities, particularly as we continue the research and development of, initiate clinical studies of, and seek marketing approval for our product candidates. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to drug sales, marketing, manufacturing and distribution to the extent that such sales, marketing and distribution are not the responsibility of potential collaborators. </span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">32</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We believe our currently available funds will be sufficient to fund our existing cash flow requirements and our current operating plan commitments for more than two years. Our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement and involves risks and uncertainties, and actual results could vary as a result of a number of factors. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we currently expect. Our future capital requirements will depend on many factors, including:</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the scope, progress, results and costs of drug discovery, preclinical development, laboratory testing and clinical studies for our product candidates;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the scope, prioritization and number of our research and development programs;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the costs, timing and outcome of regulatory review of our product candidates;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">our ability to establish and maintain collaborations on favorable terms, if at all;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the achievement of milestones or occurrence of other developments that trigger payments under any collaboration agreements we obtain;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the extent to which we are obligated to reimburse, or entitled to reimbursement of, clinical study costs under future collaboration agreements, if any;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the costs of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending intellectual property-related claims;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the extent to which we acquire or in-license other product candidates and technologies;</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the costs of securing manufacturing arrangements for clinical and commercial production; and</span></div><div style="margin-bottom:12pt;padding-left:36pt;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#8226;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:14.5pt">the costs of establishing or contracting for sales and marketing capabilities if we obtain regulatory approvals to market our product candidates.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Identifying potential product candidates and conducting preclinical testing and clinical studies is a time-consuming, expensive and uncertain process that takes many years to complete, and we may never generate the necessary data or results required to obtain marketing approval and achieve drug sales. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from sales of drugs that we do not expect to be commercially available for many years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, strategic partnerships and licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interests of our common stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. We have access to an additional line of credit under the credit facility with SVB, along with funds to be earned in connection with our agreements with Merck KGaA and Asana BioSciences, if development activities are successful under those agreements. Future additional debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">If we raise funds through additional strategic partnerships or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our drug development or </span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">33</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Off-Balance Sheet Arrangements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We did not have, during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined under applicable Securities and Exchange Commission rules.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Critical accounting policies and significant judgments and estimates</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our management's discussion and analysis of our financial condition and results of operations are based on our financial statements, which have been prepared in accordance with U.S. generally accepted accounting principles. The preparation of these financial statements requires us to make judgments and estimates that affect the reported amounts of assets, liabilities, revenues, and expenses and the disclosure of contingent assets and liabilities in our financial statements. We base our estimates on historical experience, known trends and events, and various other factors that are believed to be reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions. On an ongoing basis, we evaluate our judgments and estimates in light of changes in circumstances, facts and experience. The effects of material revisions in estimates, if any, will be reflected in the financial statements prospectively from the date of change in estimates. There were no material changes to our critical accounting policies as reported in our Annual Report on Form 10-K for the year ended December&#160;31, 2019, which was filed with the SEC on February 28, 2020.</span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_85"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;3.&#160;Quantitative and Qualitative Disclosures About Market Risk</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We are exposed to market risk-related to changes in interest rates. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates, particularly because our investments, including cash equivalents and marketable securities are invested in U.S. Treasury obligations, commercial paper and corporate bonds. However, we believe that due to the short-term duration of our investment portfolio and low-risk profile of our investments, an immediate 100 basis points change in interest rates would not have a material effect on the fair market value of our investments portfolio.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We are currently not exposed to market risk related to changes in foreign currency exchange rates, but we may contract with vendors that are located in Asia and Europe and may be subject to fluctuations in foreign currency rates at that time.</span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_88"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;4.&#160;Controls and Procedures</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Management&#8217;s Evaluation of our Disclosure Controls and Procedures</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">We maintain &#8220;disclosure controls and procedures,&#8221; as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the Exchange Act), that are designed to ensure that information required to be disclosed in the reports that we file or submit under the Exchange Act is (i) recorded, processed, summarized and reported within the time periods specified in the SEC&#8217;s rules and forms and (ii) accumulated and communicated to our management, including our principal executive and principal financial officer, as appropriate to allow timely decisions regarding required disclosure. Our management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and our management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Our disclosure controls and procedures are designed to provide reasonable assurance of achieving their control objectives.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Our management, with the participation of our principal executive officer and principal financial officer, has evaluated the effectiveness of our disclosure controls and procedures as of September&#160;30, 2020, the end of the period covered by this Quarterly Report on Form 10-Q. Based upon such evaluation, our principal executive officer and principal financial officer have concluded that our disclosure controls and procedures were effective at the reasonable assurance level as of such date.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">34</span></div></div></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Changes in Internal Control over Financial Reporting</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">There was no change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the quarter ended September&#160;30, 2020 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.</span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">35</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_91"></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">PART&#160;II&#160;- OTHER INFORMATION</span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_94"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;1.&#160;Legal Proceedings</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">From time to time, we may be subject to various legal proceedings and claims that arise in the ordinary course of our business activities. Although the results of litigation and claims cannot be predicted with certainty, as of the date of this Quarterly Report on Form 10-Q, we do not believe we are party to any claim or litigation, the outcome of which, if determined adversely to us, would individually or in the aggregate be reasonably expected to have a material adverse effect on our business. Regardless of the outcome, litigation can have an adverse impact on us because of defense and settlement costs, diversion of management resources and other factors. </span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_97"></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;1A.&#160;Risk Factors</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Risk Factors</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">There have been no material changes to the Company&#8217;s risk factors as set forth in Part I, Item 1A of the Company&#8217;s Annual Report on Form 10-K, as filed with the SEC on February 28, 2020, other than those set forth in  "Part II, Item 1A&#8212;Risk Factors" in our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2020, as filed with the SEC on May 8, 2020.</span></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_100"></div><div style="-sec-extract:summary;margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Item&#160;6.&#160;Exhibits.</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:18.130%"></td><td style="width:0.1%"></td><td style="width:0.1%"></td><td style="width:1.883%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:77.587%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT 3.1</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="https://www.sec.gov/Archives/edgar/data/1442836/000110465917044267/a17-17109_1ex3d1.htm">Fifth Amended and Restated Certificate of Incorporation (incorporated by reference to Exhibit 3.1 to the Company&#8217;s Current Report on Form 8-K, filed on July 10, 2017).</a></span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT 3.2</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="https://www.sec.gov/Archives/edgar/data/1442836/000110465917044267/a17-17109_1ex3d2.htm">Amended and Restated Bylaws (incorporated by reference to Exhibit 3.2 to the Company&#8217;s Current Report on Form 8-K, filed on July 10, 2017).</a></span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT 10.1</span></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration:underline"><a style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%;text-decoration:underline" href="https://www.sec.gov/Archives/edgar/data/1442836/000110465920102013/tm2030113d1_ex10-1.htm">Second Amendment to Loan and Security Agreement, dated August 28, 2020, by and between Mersana Therapeutics, Inc., and Silicon Valley Bank (incorporated by reference to Exhibit 10.1 to the Company&#8217;s Current Report on Form 8-K, filed on September 3,2020).</a></span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:115%"> </span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT&#160;31.1</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="exhibit31110-qfy2020q3.htm">Rule&#160;13a&#8212;14(a)&#160;/ 15d&#8212;14(a)&#160;Certifications&#160;&#8212; Chief Executive Officer.</a></span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT&#160;31.2</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="exhibit31210-qfy2020q3.htm">Rule&#160;13a&#8212;14(a)&#160;/ 15d&#8212;14(a)&#160;Certifications&#160;&#8212; Principal Financial Officer.</a></span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT&#160;32.1</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline"><a style="-sec-extract:exhibit;color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%;text-decoration:underline" href="exhibit32110-qfy2020q3.htm">Section&#160;1350 Certifications.</a></span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT&#160;101</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">The following financial and related information from Mersana Therapeutics, Inc.&#8217;s Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, formatted in Inline eXtensible Business Reportable Language (iXBRL) includes: (i) the Condensed Consolidated Balance Sheet; (ii) the Condensed Consolidated Statement of Operations and Comprehensive Income (Loss); (iii) the Condensed Consolidated Statement of Changes in Stockholders' Equity; (iv) the Condensed Consolidated Statement of Cash Flows; and, (v) Notes to Condensed Consolidated Financial Statements.</span></div></td></tr><tr style="height:3pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">EXHIBIT&#160;104</span></td><td colspan="3" style="padding:2px 1pt;text-align:right;vertical-align:top"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">-</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">The cover page from the Company&#8217;s Quarterly Report on Form 10-Q for the quarter ended September 30, 2020, formatted in Inline XBRL (contained in Exhibit 101).</span></div></td></tr></table></div><div style="margin-bottom:12pt"><span><br/></span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="-sec-extract:summary;margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">36</span></div></div></div><div id="i6ce3b7e0c0eb4e7f893dd1da12a2db6f_103"></div><hr style="page-break-after:always"/><div style="min-height:72pt;width:100%"><div style="margin-bottom:12pt"><span style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline"><a style="color:#0000ff;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;text-decoration:underline" href="#i6ce3b7e0c0eb4e7f893dd1da12a2db6f_10">Table of Contents</a></span></div></div><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%;text-decoration:underline">SIGNATURES</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.</span></div><div style="margin-bottom:6pt;text-align:center"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"></td><td style="width:46.496%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:3.387%"></td><td style="width:0.1%"></td><td style="width:1.0%"></td><td style="width:46.817%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="6" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Mersana Therapeutics, Inc.</span></td></tr><tr style="height:14pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="6" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Dated: November 9, 2020</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">By:</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">/s/ Anna Protopapas</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Anna Protopapas<br/>President and Chief Executive Officer</span></td></tr><tr style="height:14pt"><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Dated: November 9, 2020</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">By:</span></td><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">/s/ Brian DeSchuytner</span></td></tr><tr><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="padding:0 1pt"></td><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Brian DeSchuytner<br/>Senior Vice President, Finance &amp; Product Strategy</span></td></tr></table></div><div style="margin-bottom:12pt;text-align:center"><span><br/></span></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div style="margin-bottom:12pt;text-align:center"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">37</span></div></div></div></body></html>
</XBRL>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-31.1
<SEQUENCE>2
<FILENAME>exhibit31110-qfy2020q3.htm
<DESCRIPTION>EX-31.1
<TEXT>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head>
<!-- Document created using Wdesk -->
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<title>Document</title></head><body><div id="i079aead80e674af2b3000e238f18fee8_1"></div><div style="min-height:72pt;width:100%"><div style="text-align:right"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Exhibit 31.1</font></div></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Certification of Principal Executive Officer pursuant to Exchange Act Rules 13a-14(a</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">) &#160;</font></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">and 15d-14(a), as adopted pursuant to Section&#160;302 of Sarbanes-Oxley Act of 2002</font></div><div style="margin-bottom:6pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">I, Anna Protopapas, certify that&#58; &#160;</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">1.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">I have reviewed this Quarterly Report on Form 10-Q of Mersana Therapeutics, Inc.&#59;</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">2.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report&#59;</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">3.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report&#59;</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">4.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">The registrant&#8217;s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have&#58;</font></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">a)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.24pt">Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared&#59;</font></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">b)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:9.67pt">Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles&#59;</font></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">c)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.24pt">Evaluated the effectiveness of the registrant&#8217;s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation&#59; and</font></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">d)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:9.67pt">Disclosed in this report any change in the registrant&#8217;s internal control over financial reporting that occurred during the registrant&#8217;s most recent fiscal quarter (the registrant&#8217;s fourth fiscal quarter in the case of an annual report), that has materially affected, or is reasonably likely to materially affect, the registrant&#8217;s internal control over financial reporting&#59; and</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">5.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions)&#58;</font></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">a)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.24pt">All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information&#59; and</font></div><div style="margin-bottom:6pt;padding-left:36pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">b)</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:9.67pt">Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.</font></div><div style="margin-bottom:6pt;text-align:right"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:52.403%"><tr><td style="width:1.0%"></td><td style="width:98.900%"></td><td style="width:0.1%"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Mersana Therapeutics, Inc.</font></td></tr><tr style="height:15pt"><td colspan="3" style="padding:0 1pt"></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#47;s&#47; Anna Protopapas</font></td></tr><tr><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Anna Protopapas</font></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">President and Chief Executive Officer<br>(Principal Executive Officer)</font></td></tr></table></div><div style="margin-bottom:6pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Dated&#58;&#160;November&#160;9, 2020</font></div><div style="height:72pt;position:relative;width:100%"><div style="bottom:0;position:absolute;width:100%"><div><font><br></font></div></div></div></body></html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-31.2
<SEQUENCE>3
<FILENAME>exhibit31210-qfy2020q3.htm
<DESCRIPTION>EX-31.2
<TEXT>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head>
<!-- Document created using Wdesk -->
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<title>Document</title></head><body><div id="i2dbae1603809420aa4bc4cd9fa3ae12a_1"></div><div style="min-height:72pt;width:100%"><div style="text-align:right"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Exhibit 31.2</font></div></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Certification of Principal Financial Officer pursuant to Exchange Act Rules 13a-14(a)</font></div><div style="margin-bottom:6pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">and 15d-14(a), as adopted pursuant to Section&#160;302 of Sarbanes-Oxley Act of 2002</font></div><div style="margin-bottom:6pt;text-align:justify"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">I, Brian DeSchuytner, certify that&#58;</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">1.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">I have reviewed this Quarterly Report on Form 10-Q of Mersana Therapeutics, Inc.&#59;</font></div><div style="margin-bottom:6pt;padding-left:18pt;text-indent:-18pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">2.</font><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%;padding-left:10.5pt">Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under 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<title>Document</title></head><body><div id="ia37f6aefc5d243088958bdb035b96296_1"></div><div style="min-height:72pt;width:100%"><div style="text-align:right"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Exhibit 32.1</font></div></div><div style="text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT</font></div><div style="margin-bottom:12pt;text-align:center"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002</font></div><div style="margin-bottom:6pt"><font style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In connection with the Quarterly Report on Form 10-Q of Mersana Therapeutics, Inc. 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<DOCUMENT>
<TYPE>EX-101.CAL
<SEQUENCE>6
<FILENAME>mrsn-20200930_cal.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION CALCULATION LINKBASE DOCUMENT
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  <link:roleRef roleURI="http://www.mersana.com/role/LeasesFutureminimumleasepaymentsDetails" xlink:type="simple" xlink:href="mrsn-20200930.xsd#LeasesFutureminimumleasepaymentsDetails"/>
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    <link:loc xlink:type="locator" xlink:label="loc_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty_5031a2e5-a4b4-4c75-89b0-60efe2ebd23e" xlink:href="mrsn-20200930.xsd#mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty"/>
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    <link:loc xlink:type="locator" xlink:label="loc_mrsn_MilestonePayment_d55c3cdd-693d-4a17-9ec1-6fcba4fe3e15" xlink:href="mrsn-20200930.xsd#mrsn_MilestonePayment"/>
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</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.LAB
<SEQUENCE>8
<FILENAME>mrsn-20200930_lab.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
<TEXT>
<XBRL>
<?xml version="1.0" encoding="UTF-8"?>

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<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
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  <link:roleRef roleURI="http://www.xbrl.org/2009/role/netLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd#netLabel"/>
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  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedLabel"/>
  <link:roleRef roleURI="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd#negatedTotalLabel"/>
  <link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_1718b3f5-86b4-43f8-b66a-2c60a04cd198_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
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    <link:label id="lab_dei_DocumentType_71c5f0a4-0d2a-46d1-945d-711057e7a1fa_terseLabel_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Type</link:label>
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    <link:label id="lab_mrsn_CollaborationAndCommercialLicenseAgreementMerckKgaaMember_9d737829-3fdf-455e-b8a7-6548a2b6c1e1_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationAndCommercialLicenseAgreementMerckKgaaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Merck KGaA</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_4cdfda30-ecc8-4834-8071-ea2ed9ceac2c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Granted (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_WarrantTwoMember_72056fad-4018-473b-b24b-7954417eea8f_terseLabel_en-US" xlink:label="lab_mrsn_WarrantTwoMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant Two</link:label>
    <link:label id="lab_mrsn_WarrantTwoMember_label_en-US" xlink:label="lab_mrsn_WarrantTwoMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant Two [Member]</link:label>
    <link:label id="lab_mrsn_WarrantTwoMember_documentation_en-US" xlink:label="lab_mrsn_WarrantTwoMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Security, two, that gives the holder the right to purchase shares of stock in accordance with the terms of the instrument, usually upon payment of a specified amount with an exercise price of $0.0001 per share. Referred to as the "Exchange Warrants".</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_WarrantTwoMember" xlink:href="mrsn-20200930.xsd#mrsn_WarrantTwoMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_WarrantTwoMember" xlink:to="lab_mrsn_WarrantTwoMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_55edb989-69f4-4998-a27d-f91bb27eb424_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable securities</link:label>
    <link:label id="lab_us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]</link:label>
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    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_5f48c513-8640-47bf-9dd2-33e8c8efe079_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unamortized issuance costs</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_aa34afb5-76f3-4316-9bc6-472a19df28bb_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities and stockholders&#8217; equity</link:label>
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    <link:label id="lab_us-gaap_LineOfCreditMember_879d5868-63fc-4845-87df-c2dc1059856f_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit</link:label>
    <link:label id="lab_us-gaap_LineOfCreditMember_label_en-US" xlink:label="lab_us-gaap_LineOfCreditMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit [Member]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditMember" xlink:to="lab_us-gaap_LineOfCreditMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f95e930c-5d6d-4d1f-b8ed-20de7e71e610_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock options</link:label>
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    <link:label id="lab_mrsn_StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised_3fc4f4c9-af6e-4cc8-93e0-20b1855589c0_terseLabel_en-US" xlink:label="lab_mrsn_StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercise of stock options and warrants</link:label>
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    <link:label id="lab_dei_SecurityExchangeName_49cb16db-f4d5-4a53-87e1-2da7bbd9f499_terseLabel_en-US" xlink:label="lab_dei_SecurityExchangeName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Security Exchange Name</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesCurrent_fbe922da-8164-47dd-aa8e-61f6b62587b5_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total current liabilities</link:label>
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    <link:label id="lab_mrsn_CollaborationArrangementsMilestonePaymentReceivableNextMilestone_af812906-a940-4dc7-9c31-783d8fc1654f_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationArrangementsMilestonePaymentReceivableNextMilestone" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Next potential milestone payment eligible to receive</link:label>
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    <link:label id="lab_us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_cead9045-1043-4bb6-ab4b-8957d6819011_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of changes in the balances of our contract assets and liabilities and recognized revenue</link:label>
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    <link:label id="lab_mrsn_BetweenAugust282021AndAugust282022Member_02728cf2-4a82-4d06-b17f-ca0a16445968_terseLabel_en-US" xlink:label="lab_mrsn_BetweenAugust282021AndAugust282022Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Between August 28, 2021 And August 28, 2022</link:label>
    <link:label id="lab_mrsn_BetweenAugust282021AndAugust282022Member_label_en-US" xlink:label="lab_mrsn_BetweenAugust282021AndAugust282022Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Between August 28, 2021 And August 28, 2022 [Member]</link:label>
    <link:label id="lab_mrsn_BetweenAugust282021AndAugust282022Member_documentation_en-US" xlink:label="lab_mrsn_BetweenAugust282021AndAugust282022Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Between August 28, 2021 And August 28, 2022</link:label>
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    <link:label id="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_ac981fdc-d121-4bc3-8fdf-3d1fb89864b8_verboseLabel_en-US" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Prepaid expenses and other current assets</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableRateDomain" xlink:to="lab_us-gaap_VariableRateDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_VariableRateAxis_c80650ad-38cb-44e0-bbad-66ca0594c13b_terseLabel_en-US" xlink:label="lab_us-gaap_VariableRateAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Variable Rate [Axis]</link:label>
    <link:label id="lab_us-gaap_VariableRateAxis_label_en-US" xlink:label="lab_us-gaap_VariableRateAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Variable Rate [Axis]</link:label>
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    <link:label id="lab_us-gaap_RestrictedCashAssetStatementOfFinancialPositionExtensibleList_61257217-413e-4fbe-a4ed-fd16ee2378e2_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCashAssetStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted cash, Balance Sheet Location</link:label>
    <link:label id="lab_us-gaap_RestrictedCashAssetStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_RestrictedCashAssetStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Cash, Asset, Statement of Financial Position [Extensible List]</link:label>
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    <link:label id="lab_us-gaap_CommitmentsAndContingencies_d404a218-7568-4b96-9597-76be37c97d19_verboseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commitments (Note&#160;11)</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue_baef2173-a52b-4750-bdd6-46071987e5c1_totalLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease payments</link:label>
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    <link:label id="lab_us-gaap_AssetsAbstract_9d14cc50-e541-414d-8eb1-d96a8d430032_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets</link:label>
    <link:label id="lab_us-gaap_AssetsAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets [Abstract]</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_63ed42fe-2e1d-4bf8-8541-7e8915dfd204_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Vesting period (in years)</link:label>
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    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_73be1219-4897-4827-b627-70660c0a761c_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy_899225c1-ae94-4a5e-b167-429ff646acfc_verboseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Assets</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
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    <link:label id="lab_dei_EntityAddressStateOrProvince_bbf7938b-c4a6-4e9b-8c0a-ce6b94e0c5c1_terseLabel_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, State or Province</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_fb913e37-e3e2-46af-85e5-d592d686a036_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Vested (in shares)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
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    <link:label id="lab_mrsn_ContractWithCustomerLiabilityIncrease_ac7c2c8a-d3d4-431b-8978-e4ea6f028faf_terseLabel_en-US" xlink:label="lab_mrsn_ContractWithCustomerLiabilityIncrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred revenue, Additions</link:label>
    <link:label id="lab_mrsn_ContractWithCustomerLiabilityIncrease_label_en-US" xlink:label="lab_mrsn_ContractWithCustomerLiabilityIncrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contract with Customer, Liability, Increase</link:label>
    <link:label id="lab_mrsn_ContractWithCustomerLiabilityIncrease_documentation_en-US" xlink:label="lab_mrsn_ContractWithCustomerLiabilityIncrease" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of increase in obligation to transfer good or service to customer for which consideration has been received or is receivable.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ContractWithCustomerLiabilityIncrease" xlink:href="mrsn-20200930.xsd#mrsn_ContractWithCustomerLiabilityIncrease"/>
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    <link:label id="lab_us-gaap_AccountsPayableCurrent_8f280303-c34b-4fac-8a4f-a0cb195f90dd_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts payable</link:label>
    <link:label id="lab_us-gaap_AccountsPayableCurrent_label_en-US" xlink:label="lab_us-gaap_AccountsPayableCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts Payable, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableCurrent" xlink:to="lab_us-gaap_AccountsPayableCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_3cc1f3a9-c75c-4be3-85f1-d545a8e36a9f_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2023</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Term Debt, Maturity, Year Three</link:label>
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    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock_9cecf45e-0a09-4f16-bca5-c37ba5e65b85_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts Payable and Accrued Liabilities Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:to="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCommitmentsTable_ef7b12c8-8cd6-48cc-8b0f-d8f68cd68b2d_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCommitmentsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Commitments [Table]</link:label>
    <link:label id="lab_us-gaap_OtherCommitmentsTable_label_en-US" xlink:label="lab_us-gaap_OtherCommitmentsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Commitments [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCommitmentsTable" xlink:to="lab_us-gaap_OtherCommitmentsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetainedEarningsAccumulatedDeficit_84d24208-2f81-40e1-8344-f534d43b7726_terseLabel_en-US" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated deficit</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_1744ae20-5a21-4162-a645-b296d4de52d3_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease right-of-use assets</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseRightOfUseAsset_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Right-of-Use Asset</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:to="lab_us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract_0582aa2d-373b-46f1-be3a-f1e3475d9216_terseLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash, cash equivalents and restricted cash</link:label>
    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract_label_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract"/>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_d690146c-a917-47b4-82f4-a1c7009d104c_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2021</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_e4eb8c5d-c9de-4267-ae5d-31adad678ce0_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2021</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year One</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_79f48f20-9966-4a40-8f68-a78bc4bba722_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Outstanding at beginning of period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_146d2990-ea95-4d02-8cdd-aad463c96e11_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Outstanding at end of period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
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    <link:label id="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_deb73508-d548-4233-8643-ac9cc9210d50_terseLabel_en-US" xlink:label="lab_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">New Accounting pronouncements</link:label>
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    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheFiveMember_e23e4e58-4918-48a1-bd04-2b9806476274_terseLabel_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheFiveMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Five</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheFiveMember_label_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheFiveMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Five [Member]</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheFiveMember_documentation_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheFiveMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Five</link:label>
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    <link:label id="lab_mrsn_LicenseAgreementsMember_aa4f61c0-ee2d-4e84-b6de-3a0dcf1dd59a_terseLabel_en-US" xlink:label="lab_mrsn_LicenseAgreementsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">License agreements</link:label>
    <link:label id="lab_mrsn_LicenseAgreementsMember_label_en-US" xlink:label="lab_mrsn_LicenseAgreementsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">License Agreements [Member]</link:label>
    <link:label id="lab_mrsn_LicenseAgreementsMember_documentation_en-US" xlink:label="lab_mrsn_LicenseAgreementsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Information pertaining to license agreements.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_LicenseAgreementsMember" xlink:href="mrsn-20200930.xsd#mrsn_LicenseAgreementsMember"/>
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    <link:label id="lab_us-gaap_SharesOutstanding_d1767547-4773-4b91-b408-46bc8a22dbf9_periodStartLabel_en-US" xlink:label="lab_us-gaap_SharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance at beginning of period (in shares)</link:label>
    <link:label id="lab_us-gaap_SharesOutstanding_a382a19e-d90b-4793-a5ea-2e3e77fb4079_periodEndLabel_en-US" xlink:label="lab_us-gaap_SharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance at end of period (in shares)</link:label>
    <link:label id="lab_us-gaap_SharesOutstanding_label_en-US" xlink:label="lab_us-gaap_SharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares, Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharesOutstanding" xlink:to="lab_us-gaap_SharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockValue_6951f47e-a81a-40aa-965c-01a8a5e749fc_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, $0.0001 par value; 25,000,000 shares authorized; 0 shares issued and outstanding at September&#160;30, 2020 and December&#160;31, 2019, respectively</link:label>
    <link:label id="lab_us-gaap_PreferredStockValue_label_en-US" xlink:label="lab_us-gaap_PreferredStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Value, Issued</link:label>
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    <link:label id="lab_mrsn_BetweenAugust282022AndNovember12024Member_1614214d-910a-46df-bcfc-6198aeccd1a0_terseLabel_en-US" xlink:label="lab_mrsn_BetweenAugust282022AndNovember12024Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Between August 28, 2022 And November 1, 2024</link:label>
    <link:label id="lab_mrsn_BetweenAugust282022AndNovember12024Member_label_en-US" xlink:label="lab_mrsn_BetweenAugust282022AndNovember12024Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Between August 28, 2022 And November 1, 2024 [Member]</link:label>
    <link:label id="lab_mrsn_BetweenAugust282022AndNovember12024Member_documentation_en-US" xlink:label="lab_mrsn_BetweenAugust282022AndNovember12024Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Between August 28, 2022 And November 1, 2024</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_BetweenAugust282022AndNovember12024Member" xlink:href="mrsn-20200930.xsd#mrsn_BetweenAugust282022AndNovember12024Member"/>
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    <link:label id="lab_mrsn_RevenueTransactionPriceIncreaseDecrease_f11de7ad-23bc-49ce-86ac-253a9bacac49_negatedLabel_en-US" xlink:label="lab_mrsn_RevenueTransactionPriceIncreaseDecrease" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Decrease in fees expected to be received for research and development</link:label>
    <link:label id="lab_mrsn_RevenueTransactionPriceIncreaseDecrease_label_en-US" xlink:label="lab_mrsn_RevenueTransactionPriceIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue, Transaction Price, Increase (Decrease)</link:label>
    <link:label id="lab_mrsn_RevenueTransactionPriceIncreaseDecrease_documentation_en-US" xlink:label="lab_mrsn_RevenueTransactionPriceIncreaseDecrease" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (decrease) in transaction price during the period due to change in fees expected to be received for research and development activities.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_RevenueTransactionPriceIncreaseDecrease" xlink:href="mrsn-20200930.xsd#mrsn_RevenueTransactionPriceIncreaseDecrease"/>
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    <link:label id="lab_us-gaap_OperatingExpenses_6ee5b2ca-2460-4770-b59e-3689d699df3c_totalLabel_en-US" xlink:label="lab_us-gaap_OperatingExpenses" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total operating expenses</link:label>
    <link:label id="lab_us-gaap_OperatingExpenses_label_en-US" xlink:label="lab_us-gaap_OperatingExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Expenses</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpenses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="lab_us-gaap_OperatingExpenses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_f40c567b-3177-4795-8377-d283db06bc5d_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Options exercisable, at end of period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised_4ccfb765-0e5f-4782-a913-995f568c2919_terseLabel_en-US" xlink:label="lab_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercise of common stock warrant in exchange for common stock (in shares)</link:label>
    <link:label id="lab_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised_label_en-US" xlink:label="lab_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issued During Period, Shares Of Common Stock Warrants In Exchange For Common Stock Exercised</link:label>
    <link:label id="lab_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised_documentation_en-US" xlink:label="lab_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares issued during period and exercise of common stock warrant in exchange for common stock</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised" xlink:href="mrsn-20200930.xsd#mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised"/>
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    <link:label id="lab_us-gaap_CommonStockParOrStatedValuePerShare_61c1dd42-0d68-4bf9-8b49-30af84b52d61_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock, par value (in dollars per share)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
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    <link:label id="lab_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts_c5c41d71-2a1f-4cff-8fba-217ac24a6e9f_terseLabel_en-US" xlink:label="lab_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from stock issuance, net of issuance costs</link:label>
    <link:label id="lab_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts_label_en-US" xlink:label="lab_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds From Issuance Of Common Stock, Net Of Stock Issuance Costs</link:label>
    <link:label id="lab_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts_documentation_en-US" xlink:label="lab_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The net proceeds from the additional capital contribution to the entity after deducting fees, commissions and other expenses.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts" xlink:href="mrsn-20200930.xsd#mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts"/>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_b1efd6bc-6bf4-4273-ae1c-52174d6fcac0_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other comprehensive loss</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]</link:label>
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    <link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_0797422d-9024-4150-bcc7-171f8580b663_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other liabilities</link:label>
    <link:label id="lab_us-gaap_OtherLiabilitiesNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Liabilities, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesNoncurrent" xlink:to="lab_us-gaap_OtherLiabilitiesNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_fd17cc3d-79b5-4a6a-af27-d10365a8e50f_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments under capital lease obligations</link:label>
    <link:label id="lab_us-gaap_FinanceLeasePrincipalPayments_label_en-US" xlink:label="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Principal Payments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeasePrincipalPayments" xlink:to="lab_us-gaap_FinanceLeasePrincipalPayments" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets_4f966c3f-3407-482c-b891-0d9c8891c8f2_terseLabel_en-US" xlink:label="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease assets</link:label>
    <link:label id="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets_label_en-US" xlink:label="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) In Operating Lease Assets</link:label>
    <link:label id="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets_documentation_en-US" xlink:label="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The increase (decrease) during the reporting period in operating lease assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_IncreaseDecreaseInOperatingLeaseAssets" xlink:href="mrsn-20200930.xsd#mrsn_IncreaseDecreaseInOperatingLeaseAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_IncreaseDecreaseInOperatingLeaseAssets" xlink:to="lab_mrsn_IncreaseDecreaseInOperatingLeaseAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3e1e9171-6bde-4d30-917e-6e61e7997246_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock-based compensation expense</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">APIC, Share-based Payment Arrangement, Increase for Cost Recognition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheThreeMember_2343cd98-312e-4cd8-8db1-c8d660bd2136_terseLabel_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheThreeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Three</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheThreeMember_label_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheThreeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Three [Member]</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheThreeMember_documentation_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheThreeMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AmendedCreditFacilityTrancheThreeMember" xlink:href="mrsn-20200930.xsd#mrsn_AmendedCreditFacilityTrancheThreeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AmendedCreditFacilityTrancheThreeMember" xlink:to="lab_mrsn_AmendedCreditFacilityTrancheThreeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_1c4d1296-1b00-4a0b-9171-b1c23eb79444_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration revenue</link:label>
    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_label_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from Contract with Customer, Excluding Assessed Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementFrequencyDomain_b80825c8-8c4c-4186-9c05-7d947b1d9a11_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Measurement Frequency [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementFrequencyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="lab_us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber_09678523-f53c-492a-b6f7-c6d19958393b_terseLabel_en-US" xlink:label="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of targets</link:label>
    <link:label id="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber_label_en-US" xlink:label="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangements, Exclusive Targets, Number</link:label>
    <link:label id="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber_documentation_en-US" xlink:label="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of exclusive targets entity provided right to develop under terms of agreement as of balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborativeArrangementsExclusiveTargetsNumber" xlink:href="mrsn-20200930.xsd#mrsn_CollaborativeArrangementsExclusiveTargetsNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_CollaborativeArrangementsExclusiveTargetsNumber" xlink:to="lab_mrsn_CollaborativeArrangementsExclusiveTargetsNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AmendedCreditFacilityMember_d7c43d54-5d1a-45ba-8bf1-c453d04cc617_terseLabel_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amendment To Credit Facility</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityMember_label_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility [Member]</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityMember_documentation_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AmendedCreditFacilityMember" xlink:href="mrsn-20200930.xsd#mrsn_AmendedCreditFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AmendedCreditFacilityMember" xlink:to="lab_mrsn_AmendedCreditFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_2db27b3a-64d7-412e-8af6-fa01daeee87f_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expiration period</link:label>
    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_label_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:to="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementLineItems_81f9eb04-825e-410e-bdff-509a170b3579_terseLabel_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:label id="lab_us-gaap_StatementLineItems_label_en-US" xlink:label="lab_us-gaap_StatementLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementLineItems" xlink:to="lab_us-gaap_StatementLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_ee9e1c70-0bd9-4d82-b88e-52dc4755cdda_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of outstanding potentially dilutive securities excluded from calculation of diluted net loss per share</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:to="lab_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember_7dd65c99-ef6a-4b60-b6c1-80969a3899a1_terseLabel_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">ATM</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember_2ffc0af8-ec35-4c8c-b757-e6bb9560540e_verboseLabel_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program (2018 ATM)</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember_label_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program (2018 ATM) [Member]</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember_documentation_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At-the-market equity offering program to offer and sell common stock from time to time at prevailing market prices.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:href="mrsn-20200930.xsd#mrsn_AtMarketEquityOfferingProgram2018ATMMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:to="lab_mrsn_AtMarketEquityOfferingProgram2018ATMMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_0056907a-7423-435e-8372-0fc38f21869d_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangement and Arrangement Other than Collaborative [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangement and Arrangement Other than Collaborative [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable" xlink:to="lab_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementTable_d9982912-dde6-43b9-b6d7-16ad7d12d149_terseLabel_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement [Table]</link:label>
    <link:label id="lab_us-gaap_StatementTable_label_en-US" xlink:label="lab_us-gaap_StatementTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementTable" xlink:to="lab_us-gaap_StatementTable" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_RangeAxis_c2e2700c-6d0a-4ede-ac28-d8a03705a95a_terseLabel_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:label id="lab_srt_RangeAxis_label_en-US" xlink:label="lab_srt_RangeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statistical Measurement [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_RangeAxis" xlink:to="lab_srt_RangeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CreditFacilityAxis_aba89427-35dd-41f7-b6a0-c4909f6a358e_terseLabel_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:label id="lab_us-gaap_CreditFacilityAxis_label_en-US" xlink:label="lab_us-gaap_CreditFacilityAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Credit Facility [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CreditFacilityAxis" xlink:to="lab_us-gaap_CreditFacilityAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockSharesIssued_ce325873-0bec-498a-8a06-e65928594972_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, shares issued (in shares)</link:label>
    <link:label id="lab_us-gaap_PreferredStockSharesIssued_label_en-US" xlink:label="lab_us-gaap_PreferredStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Shares Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockSharesIssued" xlink:to="lab_us-gaap_PreferredStockSharesIssued" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_ef2341b2-24eb-4511-ac05-b8f8b1941de1_terseLabel_en-US" xlink:label="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant exercise price per share (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_label_en-US" xlink:label="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Warrant or Right, Exercise Price of Warrants or Rights</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:to="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessCombinationsAbstract_label_en-US" xlink:label="lab_us-gaap_BusinessCombinationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Business Combinations [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationsAbstract" xlink:to="lab_us-gaap_BusinessCombinationsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MarketableSecuritiesPolicy_0e0c7ffc-5eb1-40b0-a7df-ae0272854c37_terseLabel_en-US" xlink:label="lab_us-gaap_MarketableSecuritiesPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable Securities</link:label>
    <link:label id="lab_us-gaap_MarketableSecuritiesPolicy_label_en-US" xlink:label="lab_us-gaap_MarketableSecuritiesPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable Securities, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecuritiesPolicy" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MarketableSecuritiesPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MarketableSecuritiesPolicy" xlink:to="lab_us-gaap_MarketableSecuritiesPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareBasicAndDiluted_cfc6cb9e-932c-46df-9906-77e29b0eab52_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasicAndDiluted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareBasicAndDiluted_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasicAndDiluted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Basic and Diluted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasicAndDiluted" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasicAndDiluted" xlink:to="lab_us-gaap_EarningsPerShareBasicAndDiluted" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborationArrangementsCostsBilled_f307d27b-35b7-4581-b044-b8563ab571af_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationArrangementsCostsBilled" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of costs billed</link:label>
    <link:label id="lab_mrsn_CollaborationArrangementsCostsBilled_label_en-US" xlink:label="lab_mrsn_CollaborationArrangementsCostsBilled" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration Arrangements, Costs Billed</link:label>
    <link:label id="lab_mrsn_CollaborationArrangementsCostsBilled_documentation_en-US" xlink:label="lab_mrsn_CollaborationArrangementsCostsBilled" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of costs billed during the period under terms of agreement.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborationArrangementsCostsBilled" xlink:href="mrsn-20200930.xsd#mrsn_CollaborationArrangementsCostsBilled"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_CollaborationArrangementsCostsBilled" xlink:to="lab_mrsn_CollaborationArrangementsCostsBilled" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntitySmallBusiness_1b12e831-ea41-4a55-9481-652188e5ce82_terseLabel_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Small Business</link:label>
    <link:label id="lab_dei_EntitySmallBusiness_label_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Small Business</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntitySmallBusiness"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntitySmallBusiness" xlink:to="lab_dei_EntitySmallBusiness" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_2ce54c72-c333-4f6b-8e96-332e1a7f5f20_terseLabel_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Principles of Consolidation</link:label>
    <link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidation, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsolidationPolicyTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConsolidationPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConsolidationPolicyTextBlock" xlink:to="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_5fd562fe-0e70-48d2-9383-f8b158349320_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, Payment, Due [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:to="lab_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3ec61783-a81d-45a7-910a-f7792018f8b6_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Stockholders' Equity</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Stockholders' Equity [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="lab_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod_fa2a7b7b-1a39-4032-a8e8-033f65420481_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Period of shared development costs following effective termination date</link:label>
    <link:label id="lab_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod_label_en-US" xlink:label="lab_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration Arrangements, Shared Development Costs Effective Following Termination Date, Period</link:label>
    <link:label id="lab_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod_documentation_en-US" xlink:label="lab_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Period of time following effective termination date in which development costs were equally shared with counterparty under the terms of the agreement, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod" xlink:href="mrsn-20200930.xsd#mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod"/>
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    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember_47e5c0c1-9acb-4291-a7cb-c33207205d35_terseLabel_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program, 7.74 per Share</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember_label_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program, 7.74 per Share [Member]</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember_documentation_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program, 7.74 per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AtMarketEquityOfferingProgram774PerShareMember" xlink:href="mrsn-20200930.xsd#mrsn_AtMarketEquityOfferingProgram774PerShareMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AtMarketEquityOfferingProgram774PerShareMember" xlink:to="lab_mrsn_AtMarketEquityOfferingProgram774PerShareMember" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_30c802b7-b53a-4060-b81f-3efeaabdf2b7_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureTextBlock" xlink:to="lab_us-gaap_DebtDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_cf651343-27da-4e39-aff7-d2bad8cf7fc9_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborationAndCommercialLicenseAgreementAndSupplyAgreementMerckKgaaMember_83f8ce9d-447c-481b-bc40-bf7a1a7d30d6_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationAndCommercialLicenseAgreementAndSupplyAgreementMerckKgaaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Merck KGaA Agreement and Merck KGaA Supply Agreement</link:label>
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    <link:label id="lab_mrsn_CollaborationAndCommercialLicenseAgreementAndSupplyAgreementMerckKgaaMember_documentation_en-US" xlink:label="lab_mrsn_CollaborationAndCommercialLicenseAgreementAndSupplyAgreementMerckKgaaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents information pertaining to the Collaboration and Commercial License Agreement with Merck KGaA and the Supply Agreement with Merck KGaA.</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_14d878e9-58bb-412f-9d25-af2190491803_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net proceeds from public offering of common stock</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfCommonStock_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from Issuance of Common Stock</link:label>
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    <link:label id="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability_6f83c590-afc7-4004-a72c-ea08ff2001cd_terseLabel_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase in operating lease liability</link:label>
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    <link:label id="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability_documentation_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (decrease) in present value of lessee's discounted obligation for lease payments from operating lease due to lease modification</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability" xlink:to="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AmendmentFlag_a7c0e2f3-9a9f-4310-8691-9a33cdd3ca75_terseLabel_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amendment Flag</link:label>
    <link:label id="lab_dei_AmendmentFlag_label_en-US" xlink:label="lab_dei_AmendmentFlag" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amendment Flag</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_AmendmentFlag"/>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_b226eead-6b11-4414-83ef-32832d90b967_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommitmentsDisclosureTextBlock_40d77ad7-5f6a-4f42-8b16-eec44fec1356_terseLabel_en-US" xlink:label="lab_us-gaap_CommitmentsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commitments</link:label>
    <link:label id="lab_us-gaap_CommitmentsDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_CommitmentsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commitments Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsDisclosureTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommitmentsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsDisclosureTextBlock" xlink:to="lab_us-gaap_CommitmentsDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeFinanceLeasesTextBlock_d86fe537-a3f1-43fd-bfa7-dc4cd1e76d19_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeFinanceLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases</link:label>
    <link:label id="lab_us-gaap_LesseeFinanceLeasesTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeFinanceLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Finance Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeFinanceLeasesTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeFinanceLeasesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeFinanceLeasesTextBlock" xlink:to="lab_us-gaap_LesseeFinanceLeasesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_dbdd2dee-2f14-41f7-9946-3135a16273b4_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares authorized (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_c567223e-20c3-4a83-9623-f63a7518fb2c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares available for future issuance (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_c8ee0cd5-d1ad-42a1-b24c-e0754ca7f1a4_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued other</link:label>
    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Accrued Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherAccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheOneMember_df4e2ac4-5657-47f9-9a5a-6ac03e5fee00_terseLabel_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheOneMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche One</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheOneMember_label_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheOneMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche One [Member]</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheOneMember_documentation_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheOneMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AmendedCreditFacilityTrancheOneMember" xlink:href="mrsn-20200930.xsd#mrsn_AmendedCreditFacilityTrancheOneMember"/>
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    <link:label id="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock_3c6da5b4-49e4-4f02-a1e5-8fe94e3ee65d_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Measurements</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Measurement, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementPolicyPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:to="lab_us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_d4ad75e6-b5e8-485d-b338-bb3dc930f3fd_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash used in operating activities</link:label>
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    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrentAbstract_ca8338a8-6452-45ec-95b0-10c141b8daef_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Liabilities, Current [Abstract]</link:label>
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    <link:label id="lab_mrsn_StockIssuanceDiscountsAndCommissionsOnTransaction_d81cb680-8d69-467c-9837-911f2065f924_terseLabel_en-US" xlink:label="lab_mrsn_StockIssuanceDiscountsAndCommissionsOnTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock issuance costs</link:label>
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    <link:label id="lab_mrsn_CollaborationArrangementsDurationToTermination_f62bd7b7-ffbc-46cb-910f-ca5dd8e12299_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationArrangementsDurationToTermination" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Period of time until agreement terminated</link:label>
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    <link:label id="lab_mrsn_CollaborationArrangementsDurationToTermination_documentation_en-US" xlink:label="lab_mrsn_CollaborationArrangementsDurationToTermination" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Period of time before which agreement will be terminated due to counter party serving prior written notice, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborationArrangementsDurationToTermination" xlink:href="mrsn-20200930.xsd#mrsn_CollaborationArrangementsDurationToTermination"/>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_10f6e8b8-5d44-4596-a689-b0b1b9e09f50_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares issued (in shares)</link:label>
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    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram2020ATMMember_40e7eecf-f435-46f0-8de6-db8331130fa9_terseLabel_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram2020ATMMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program (2020 ATM)</link:label>
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    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_7a8849ba-e96d-46b8-95b8-67747f4d6a7f_totalLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amortized Cost</link:label>
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    <link:label id="lab_us-gaap_LesseeOperatingLeaseRenewalTerm_267b20ba-78b2-4ff7-bf27-38e8b19a0383_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Renewal term</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseRenewalTerm_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Renewal Term</link:label>
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    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_a8eccfcc-2000-40db-a3cc-ecbce7656513_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrecognized stock compensation cost</link:label>
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    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_19d59b53-30de-4ba3-a44e-541dbb2c3672_terseLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross Unrealized Gains</link:label>
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    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_5a0016fd-b6b6-4255-b8b0-93d47a80b028_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants_caa28bc1-5ab4-4688-b1ba-f800c501a634_terseLabel_en-US" xlink:label="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Aggregate common stock exchanged (in shares)</link:label>
    <link:label id="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants_label_en-US" xlink:label="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Warrant or Right, Shares Exchanged for Warrants</link:label>
    <link:label id="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants_documentation_en-US" xlink:label="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of common shares exchanged for warrants.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants" xlink:href="mrsn-20200930.xsd#mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants" xlink:to="lab_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_f8e22cab-8d02-42f2-b1fe-7f7f4ce277a8_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2024</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Term Debt, Maturity, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_bdc280cb-78d4-4ba2-9094-135342f1f8db_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Lived Tangible Asset [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeStockMember_33c446a8-87be-4ddc-b10d-db8266164f72_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee stock purchase plan</link:label>
    <link:label id="lab_us-gaap_EmployeeStockMember_label_en-US" xlink:label="lab_us-gaap_EmployeeStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeStockMember" xlink:to="lab_us-gaap_EmployeeStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementLocationAxis_96632988-ee45-4b7b-a84c-cefdd1e725d0_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement Location [Axis]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementLocationAxis_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement Location [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementLocationAxis" xlink:to="lab_us-gaap_IncomeStatementLocationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_d6f77614-be0e-4abf-8ecb-b95fa92afcff_terseLabel_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_label_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCommonStockSharesOutstanding" xlink:to="lab_dei_EntityCommonStockSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementLocationDomain_59055714-5abc-4867-91ca-37fcf3cbce9a_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement Location [Domain]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementLocationDomain_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement Location [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementLocationDomain" xlink:to="lab_us-gaap_IncomeStatementLocationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_8ec599fe-9d5f-4f66-816a-7cab14f0fa65_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2022</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Two</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCommitmentsLineItems_1c017ef9-bae6-401e-a782-1103be7fe076_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCommitmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commitments</link:label>
    <link:label id="lab_us-gaap_OtherCommitmentsLineItems_label_en-US" xlink:label="lab_us-gaap_OtherCommitmentsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Commitments [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCommitmentsLineItems" xlink:to="lab_us-gaap_OtherCommitmentsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_794fc7d1-2aaa-49b8-af4d-9b1f06936655_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash flows from financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock_41d5ae69-b2a9-48a6-a460-08defe324906_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of reconciliation of marketable securities from cost basis to fair value</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Available-for-sale Securities Reconciliation [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour_fb70b92b-2d2d-407f-87bf-8443e6a157df_terseLabel_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2024 and thereafter</link:label>
    <link:label id="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour_label_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, Payments, Due Year Four And After Year Four</link:label>
    <link:label id="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour_documentation_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of lessee's undiscounted obligation for lease payments for operating lease, due year four and after fourth fiscal year following current fiscal year.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:href="mrsn-20200930.xsd#mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:to="lab_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquityNoteAbstract_eb590005-d35f-459c-a616-227e7fd4c6f0_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityNoteAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Note [Abstract]</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityNoteAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityNoteAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Note [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract" xlink:to="lab_us-gaap_StockholdersEquityNoteAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_RevenueTransactionPriceAmount_53026d1a-96f5-4aa9-a9a5-e5dc3834626c_terseLabel_en-US" xlink:label="lab_mrsn_RevenueTransactionPriceAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Transaction price</link:label>
    <link:label id="lab_mrsn_RevenueTransactionPriceAmount_label_en-US" xlink:label="lab_mrsn_RevenueTransactionPriceAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue, Transaction Price, Amount</link:label>
    <link:label id="lab_mrsn_RevenueTransactionPriceAmount_documentation_en-US" xlink:label="lab_mrsn_RevenueTransactionPriceAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of transaction price which represents the amount of consideration the entity expects to receive for transfer of goods and services. Amount is net of estimated fees associated with research and development activities.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_RevenueTransactionPriceAmount" xlink:href="mrsn-20200930.xsd#mrsn_RevenueTransactionPriceAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_RevenueTransactionPriceAmount" xlink:to="lab_mrsn_RevenueTransactionPriceAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_DebtCovenantPeriodDomain_f00678fc-0ecd-46a8-be84-f4631bbab0d7_terseLabel_en-US" xlink:label="lab_mrsn_DebtCovenantPeriodDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Covenant, Period [Domain]</link:label>
    <link:label id="lab_mrsn_DebtCovenantPeriodDomain_label_en-US" xlink:label="lab_mrsn_DebtCovenantPeriodDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Covenant, Period [Domain]</link:label>
    <link:label id="lab_mrsn_DebtCovenantPeriodDomain_documentation_en-US" xlink:label="lab_mrsn_DebtCovenantPeriodDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Covenant, Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_DebtCovenantPeriodDomain" xlink:href="mrsn-20200930.xsd#mrsn_DebtCovenantPeriodDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_DebtCovenantPeriodDomain" xlink:to="lab_mrsn_DebtCovenantPeriodDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_65fbeebb-be41-407d-8c0b-49a6beac0bc4_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2023</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Three</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_a9c6efdb-5b98-4beb-a06b-5de6b6177835_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_label_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Assets, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsNoncurrent" xlink:to="lab_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameAxis_bfcb8504-ddef-49da-a82d-9ce15bdbf04e_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:label id="lab_us-gaap_PlanNameAxis_label_en-US" xlink:label="lab_us-gaap_PlanNameAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameAxis" xlink:to="lab_us-gaap_PlanNameAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues_e0c9ebd4-0a9b-4a4c-9df1-c83feba9b609_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Issuance of common stock under public offering, net of issuance costs</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issued During Period, Value, New Issues</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Assets_6ee63a75-3c41-452d-b5f2-e7f06b7d170b_totalLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_Assets_label_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestExpenseDebt_8c35f44f-c97e-4119-94d7-e81cda095365_terseLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest expense</link:label>
    <link:label id="lab_us-gaap_InterestExpenseDebt_label_en-US" xlink:label="lab_us-gaap_InterestExpenseDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Expense, Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpenseDebt" xlink:to="lab_us-gaap_InterestExpenseDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_MilestonePayment_ac7674aa-92f5-4106-a6ba-bf4ff7f20a54_terseLabel_en-US" xlink:label="lab_mrsn_MilestonePayment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Milestone Payment</link:label>
    <link:label id="lab_mrsn_MilestonePayment_label_en-US" xlink:label="lab_mrsn_MilestonePayment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Milestone Payment</link:label>
    <link:label id="lab_mrsn_MilestonePayment_documentation_en-US" xlink:label="lab_mrsn_MilestonePayment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The cash outflow during the period for milestone payments under the terms of the agreement.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_MilestonePayment" xlink:href="mrsn-20200930.xsd#mrsn_MilestonePayment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_MilestonePayment" xlink:to="lab_mrsn_MilestonePayment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_cff9d39e-f747-49b8-9319-394f5fbf0ead_periodStartLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unvested at beginning of period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c1ed927c-57e8-4909-9271-4d72b110c59d_periodEndLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unvested at end of period (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_Security12bTitle_d369ea59-4eab-41c5-b9b8-49de41bc7ae4_terseLabel_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:label id="lab_dei_Security12bTitle_label_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_Security12bTitle"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_Security12bTitle" xlink:to="lab_dei_Security12bTitle" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborativeArrangementsUpfrontPayment_8018d36a-4ded-4bfd-9e5f-25588cc010d3_terseLabel_en-US" xlink:label="lab_mrsn_CollaborativeArrangementsUpfrontPayment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Upfront payment received</link:label>
    <link:label id="lab_mrsn_CollaborativeArrangementsUpfrontPayment_label_en-US" xlink:label="lab_mrsn_CollaborativeArrangementsUpfrontPayment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangements, Upfront Payment</link:label>
    <link:label id="lab_mrsn_CollaborativeArrangementsUpfrontPayment_documentation_en-US" xlink:label="lab_mrsn_CollaborativeArrangementsUpfrontPayment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of upfront payment received during the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborativeArrangementsUpfrontPayment" xlink:href="mrsn-20200930.xsd#mrsn_CollaborativeArrangementsUpfrontPayment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_CollaborativeArrangementsUpfrontPayment" xlink:to="lab_mrsn_CollaborativeArrangementsUpfrontPayment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_fb8183e7-ca54-4cc5-9c99-dee40c43b6f9_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance leases</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Payment, Due [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:to="lab_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_2e8a25a5-cf1b-4bda-9c8d-9097f4fe7112_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted-average grant date fair value of options granted (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_beaea62d-89fa-40e7-91d5-88ae3addcacb_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Antidilutive Securities [Axis]</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Antidilutive Securities [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock_8cc4fa2c-445b-4f2c-8b5a-ace23bb8366e_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Nature of business and basis of presentation</link:label>
    <link:label id="lab_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock_label_en-US" xlink:label="lab_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Business Description and Basis of Presentation [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock" xlink:to="lab_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_01f46c9a-25d4-4161-8939-3f843d7187da_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of future minimum payments under finance leases</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Fiscal Year Maturity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:to="lab_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InterestExpense_bd783038-1c9a-4e07-b0a6-914a357ef9f9_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest expense</link:label>
    <link:label id="lab_us-gaap_InterestExpense_label_en-US" xlink:label="lab_us-gaap_InterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestExpense" xlink:to="lab_us-gaap_InterestExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DepreciationDepletionAndAmortization_6b23be3e-f03a-441d-af87-64831d1669b4_terseLabel_en-US" xlink:label="lab_us-gaap_DepreciationDepletionAndAmortization" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Depreciation</link:label>
    <link:label id="lab_us-gaap_DepreciationDepletionAndAmortization_label_en-US" xlink:label="lab_us-gaap_DepreciationDepletionAndAmortization" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Depreciation, Depletion and Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DepreciationDepletionAndAmortization" xlink:to="lab_us-gaap_DepreciationDepletionAndAmortization" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductOrServiceAxis_78cfe255-7de8-416a-993c-eef239f65783_terseLabel_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Axis]</link:label>
    <link:label id="lab_srt_ProductOrServiceAxis_label_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductOrServiceAxis" xlink:to="lab_srt_ProductOrServiceAxis" xlink:type="arc" order="1"/>
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    <link:label id="lab_mrsn_PublicStockOfferingMember_a5193b86-bbac-4ced-9ef5-0cb6ad8ebaaa_terseLabel_en-US" xlink:label="lab_mrsn_PublicStockOfferingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Public Stock Offering</link:label>
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    <link:label id="lab_mrsn_PublicStockOfferingMember_documentation_en-US" xlink:label="lab_mrsn_PublicStockOfferingMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Public Stock Offering</link:label>
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    <link:label id="lab_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_5bdd00ac-a4eb-4256-8bd5-e9516d32b452_terseLabel_en-US" xlink:label="lab_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration agreements</link:label>
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    <link:label id="lab_us-gaap_IncomeStatementAbstract_a96ca839-11b1-4085-9899-5d50e017ad93_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement [Abstract]</link:label>
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    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember_9c49ae8d-bfae-42ce-bba9-920cd44f3677_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss)</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseLiabilityNoncurrent_480c7c5e-3607-424a-a403-ebb5aed61592_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liabilities</link:label>
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    <link:label id="lab_us-gaap_UseOfEstimates_34623a01-141a-4f0c-8ef4-29dd842d6abe_terseLabel_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Use of Estimates</link:label>
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    <link:label id="lab_us-gaap_AssetsCurrentAbstract_3afe3582-20c0-44f0-b26d-1282b84d5a44_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current assets:</link:label>
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    <link:label id="lab_us-gaap_InvestmentIncomeInterest_a0125a5d-7b45-4da1-bafd-da318a06da56_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentIncomeInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest income</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentIncomeInterest" xlink:to="lab_us-gaap_InvestmentIncomeInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_DevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember_085ffeb0-ec10-4a5f-bc24-1aff690e3a10_terseLabel_en-US" xlink:label="lab_mrsn_DevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">XMT-1522 Agreement</link:label>
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    <link:label id="lab_mrsn_DebtInstrumentDebtDefaultAdditionalRate_616411d7-8c48-4665-b053-a28955c38a72_terseLabel_en-US" xlink:label="lab_mrsn_DebtInstrumentDebtDefaultAdditionalRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional rate in event of default</link:label>
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    <link:label id="lab_us-gaap_ComprehensiveIncomeNetOfTax_d826e311-ba3e-48fe-99f0-344fe1d33b85_totalLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNetOfTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Comprehensive loss</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree_d9777cc1-6eb0-45aa-bd9b-ff9b35f534fa_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2023</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_8a854d61-9135-4910-91e0-fd73ef14ea73_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expected dividend yield</link:label>
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    <link:label id="lab_us-gaap_PreferredStockParOrStatedValuePerShare_84f462fa-2413-4411-9d05-f73a793e2bd6_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, par value (in dollars per share)</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:to="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_b32d1dea-683c-4ef5-aaa0-023ff57579af_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2021</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Term Debt, Maturity, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent_84bbaca4-720d-4291-aaf7-ab88edd82420_terseLabel_en-US" xlink:label="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued professional fees and insurance</link:label>
    <link:label id="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent_label_en-US" xlink:label="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Professional Fees And Insurance, Current</link:label>
    <link:label id="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent_documentation_en-US" xlink:label="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received and insurance. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AccruedProfessionalFeesAndInsuranceCurrent" xlink:href="mrsn-20200930.xsd#mrsn_AccruedProfessionalFeesAndInsuranceCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AccruedProfessionalFeesAndInsuranceCurrent" xlink:to="lab_mrsn_AccruedProfessionalFeesAndInsuranceCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember_e42772bd-bbf9-4dc3-89c5-529e60eb4156_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asana BioSciences</link:label>
    <link:label id="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember_label_en-US" xlink:label="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration And Commercial License Agreement Asana Bio Sciences [Member]</link:label>
    <link:label id="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember_documentation_en-US" xlink:label="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents information pertaining to the Collaboration and Commercial License Agreement with Asana BioSciences, an existing partner.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember" xlink:href="mrsn-20200930.xsd#mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember" xlink:to="lab_mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_6b9688cd-f037-4d6c-b953-9d3372e18c45_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase of property and equipment</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments to Acquire Property, Plant, and Equipment</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CityAreaCode_597f627e-ba87-4d7a-be8d-d75c0329d6d9_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">City Area Code</link:label>
    <link:label id="lab_dei_CityAreaCode_label_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">City Area Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CityAreaCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CityAreaCode" xlink:to="lab_dei_CityAreaCode" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborationAgreementsAbstract_d0e3042f-faef-4f98-9d44-c4f6b2f1195a_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationAgreementsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration agreements</link:label>
    <link:label id="lab_mrsn_CollaborationAgreementsAbstract_label_en-US" xlink:label="lab_mrsn_CollaborationAgreementsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration agreements</link:label>
    <link:label id="lab_mrsn_CollaborationAgreementsAbstract_documentation_en-US" xlink:label="lab_mrsn_CollaborationAgreementsAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">No definition available.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborationAgreementsAbstract" xlink:href="mrsn-20200930.xsd#mrsn_CollaborationAgreementsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_CollaborationAgreementsAbstract" xlink:to="lab_mrsn_CollaborationAgreementsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentPeriodEndDate_9f2c9b64-23ff-45b7-8404-c9f22aa6614d_terseLabel_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Period End Date</link:label>
    <link:label id="lab_dei_DocumentPeriodEndDate_label_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Period End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentPeriodEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentPeriodEndDate" xlink:to="lab_dei_DocumentPeriodEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_fab5bffe-6322-4c85-b3d4-3dc07381503d_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares reserved for future issuance (in shares)</link:label>
    <link:label id="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_label_en-US" xlink:label="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Capital Shares Reserved for Future Issuance</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:to="lab_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProfitLoss_befc8644-efb4-4eff-996c-b015a4b84f80_terseLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_ProfitLoss_label_en-US" xlink:label="lab_us-gaap_ProfitLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProfitLoss" xlink:to="lab_us-gaap_ProfitLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SecurityDeposit_593d0d31-3429-450c-bafd-d26dfd31c887_terseLabel_en-US" xlink:label="lab_us-gaap_SecurityDeposit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Security deposit</link:label>
    <link:label id="lab_us-gaap_SecurityDeposit_label_en-US" xlink:label="lab_us-gaap_SecurityDeposit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Security Deposit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecurityDeposit" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SecurityDeposit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SecurityDeposit" xlink:to="lab_us-gaap_SecurityDeposit" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_34b510fd-ae85-4a8c-899b-8a65f5dbf2cb_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of stock-based compensation expense by award type</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Cost by Plan [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensation_8b5b79fe-f227-4008-8d55-0f4e7e82b9a7_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock-based compensation</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Noncash Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensation" xlink:to="lab_us-gaap_ShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_e8fad4cd-41d6-4036-bb33-3c408d1b200a_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2020 (excluding the nine months ended September 30, 2020)</link:label>
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_label_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Term Debt, Maturity, Remainder of Fiscal Year</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CoverAbstract_label_en-US" xlink:label="lab_dei_CoverAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cover [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CoverAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CoverAbstract" xlink:to="lab_dei_CoverAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_WarrantsExercisedInPeriod_18ed3123-5df7-4da6-96c4-b5dc44ee235c_terseLabel_en-US" xlink:label="lab_mrsn_WarrantsExercisedInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercise of common stock warrant in exchange for common stock (in shares)</link:label>
    <link:label id="lab_mrsn_WarrantsExercisedInPeriod_label_en-US" xlink:label="lab_mrsn_WarrantsExercisedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrants, Exercised In Period</link:label>
    <link:label id="lab_mrsn_WarrantsExercisedInPeriod_documentation_en-US" xlink:label="lab_mrsn_WarrantsExercisedInPeriod" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares of stock issued as a result of the exercise of warrants.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_WarrantsExercisedInPeriod" xlink:href="mrsn-20200930.xsd#mrsn_WarrantsExercisedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_WarrantsExercisedInPeriod" xlink:to="lab_mrsn_WarrantsExercisedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredCompensationShareBasedPaymentsMember_796ea7a8-e014-432b-b416-a3178bd92214_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCompensationShareBasedPaymentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based payments</link:label>
    <link:label id="lab_us-gaap_DeferredCompensationShareBasedPaymentsMember_label_en-US" xlink:label="lab_us-gaap_DeferredCompensationShareBasedPaymentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Compensation, Share-based Payments [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationShareBasedPaymentsMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredCompensationShareBasedPaymentsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCompensationShareBasedPaymentsMember" xlink:to="lab_us-gaap_DeferredCompensationShareBasedPaymentsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebt_ed30103a-edb5-461e-ad93-27fd7e5eb397_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_label_en-US" xlink:label="lab_us-gaap_LongTermDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebt" xlink:to="lab_us-gaap_LongTermDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_5d92f770-176a-4046-853d-7e05bce4938e_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred revenue</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Contract with Customer, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:to="lab_us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_b8fd2676-4ea5-4e62-bad5-792b4b1092db_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeasesTextBlock_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Leases [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeasesTextBlock" xlink:to="lab_us-gaap_LesseeOperatingLeasesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosuresAbstract_79b1aaa1-1682-4e2d-aa51-b38cc297aa28_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosuresAbstract_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract" xlink:to="lab_us-gaap_FairValueDisclosuresAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember_8125328b-0af9-45e9-88e5-453a574adefa_terseLabel_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program, 5.59 per Share</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember_label_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program, 5.59 per Share [Member]</link:label>
    <link:label id="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember_documentation_en-US" xlink:label="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">At Market Equity Offering Program, 5.59 per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AtMarketEquityOfferingProgram559PerShareMember" xlink:href="mrsn-20200930.xsd#mrsn_AtMarketEquityOfferingProgram559PerShareMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AtMarketEquityOfferingProgram559PerShareMember" xlink:to="lab_mrsn_AtMarketEquityOfferingProgram559PerShareMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_b76d0555-54fd-4702-9379-3b23334b7be5_negatedLabel_en-US" xlink:label="lab_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net amortization of premiums and discounts on investments</link:label>
    <link:label id="lab_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_label_en-US" xlink:label="lab_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accretion (Amortization) of Discounts and Premiums, Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:to="lab_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_cd5e841c-d37b-4d66-8329-c0c3a6a8fc74_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities_23f4315b-30e8-4b9a-99a1-97658d4db012_terseLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable securities</link:label>
    <link:label id="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities_549a1307-eb3e-462a-9871-6593e4b654c5_verboseLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value</link:label>
    <link:label id="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities_label_en-US" xlink:label="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:to="lab_us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_ebb6a38d-0844-4649-8579-27bb742fefd6_terseLabel_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementEquityComponentsAxis_label_en-US" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Components [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementEquityComponentsAxis" xlink:to="lab_us-gaap_StatementEquityComponentsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_c45045f8-16cf-4141-a46f-14e6b5dda4cb_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement [Abstract]</link:label>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_label_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="lab_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_0aad3e82-fbfb-4999-9e0e-7451246937b7_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentNameDomain" xlink:to="lab_us-gaap_DebtInstrumentNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal_cf8898e3-3289-4132-8d61-0807dc4e12a9_terseLabel_en-US" xlink:label="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Final payment as percentage of original principal amount</link:label>
    <link:label id="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal_label_en-US" xlink:label="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Final Payment, Percentage Of Original Principal</link:label>
    <link:label id="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal_documentation_en-US" xlink:label="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents the final payment as percentage of original principal amount.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" xlink:href="mrsn-20200930.xsd#mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" xlink:to="lab_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MinimumMember_ed6fc861-e885-4c1a-b0b2-e5a0b7bb816a_terseLabel_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Minimum</link:label>
    <link:label id="lab_srt_MinimumMember_label_en-US" xlink:label="lab_srt_MinimumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Minimum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MinimumMember" xlink:to="lab_srt_MinimumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities_134bd120-8047-40f5-8060-ac8e64f392aa_negatedLabel_en-US" xlink:label="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liabilities</link:label>
    <link:label id="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities_label_en-US" xlink:label="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) In Operating Lease Liabilities</link:label>
    <link:label id="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities_documentation_en-US" xlink:label="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The increase (decrease) during the reporting period in operating lease liabilities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:href="mrsn-20200930.xsd#mrsn_IncreaseDecreaseInOperatingLeaseLiabilities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:to="lab_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross_9ac56ecc-17ba-4547-b631-bbd7ae81489f_terseLabel_en-US" xlink:label="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from issuance of common stock, gross</link:label>
    <link:label id="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross_label_en-US" xlink:label="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds From Issuance Of Common Stock, Gross</link:label>
    <link:label id="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross_documentation_en-US" xlink:label="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The gross proceeds from the additional capital contribution to the entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ProceedsFromIssuanceOfCommonStockGross" xlink:href="mrsn-20200930.xsd#mrsn_ProceedsFromIssuanceOfCommonStockGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ProceedsFromIssuanceOfCommonStockGross" xlink:to="lab_mrsn_ProceedsFromIssuanceOfCommonStockGross" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheSixMember_f6561e16-8498-4fcc-b6b6-2fecd6b3b90d_terseLabel_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheSixMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Six</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheSixMember_label_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheSixMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Six [Member]</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheSixMember_documentation_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheSixMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Six</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AmendedCreditFacilityTrancheSixMember" xlink:href="mrsn-20200930.xsd#mrsn_AmendedCreditFacilityTrancheSixMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AmendedCreditFacilityTrancheSixMember" xlink:to="lab_mrsn_AmendedCreditFacilityTrancheSixMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrent_3b332ed4-b50f-4bcd-942e-c8ad6040c3e9_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating lease liabilities</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilityCurrent_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="lab_us-gaap_OperatingLeaseLiabilityCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_a6600be8-03d1-4e51-ac0e-3008b41d7526_verboseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Right-of-use assets obtained in exchange for financing lease liabilities</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability"/>
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    <link:label id="lab_mrsn_OfficeSpaceCambridgeMaMember_b1bf3ef3-b1a9-4dd1-859b-32803669ee97_terseLabel_en-US" xlink:label="lab_mrsn_OfficeSpaceCambridgeMaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Office space, Cambridge, MA</link:label>
    <link:label id="lab_mrsn_OfficeSpaceCambridgeMaMember_label_en-US" xlink:label="lab_mrsn_OfficeSpaceCambridgeMaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Office Space Cambridge Ma [Member]</link:label>
    <link:label id="lab_mrsn_OfficeSpaceCambridgeMaMember_documentation_en-US" xlink:label="lab_mrsn_OfficeSpaceCambridgeMaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Office space in Cambridge, MA under operating lease.</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_bb17e119-d5b1-4902-9e9d-bb490d8399b0_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of weighted average assumptions for estimating fair value of option awards</link:label>
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    <link:label id="lab_dei_EntityInteractiveDataCurrent_e8523cde-ae8b-4f10-a814-e7fdce95f1c0_terseLabel_en-US" xlink:label="lab_dei_EntityInteractiveDataCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Interactive Data Current</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_b921f37b-3a91-45b1-9787-7db2cddb3b8c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercised (in dollars per share)</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock_ca2ba1f5-e9e1-4c7b-992c-ed4390f7f1b1_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Restricted Cash and Cash Equivalents</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restrictions on Cash and Cash Equivalents [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" xlink:to="lab_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_3f3b0a1c-a083-4b5b-804c-50d8f3e004bb_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash flows from operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
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    <link:label id="lab_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised_675e1d5f-150b-4254-979b-4d9d5569cb71_terseLabel_en-US" xlink:label="lab_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercise of stock options and warrants (in shares)</link:label>
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    <link:label id="lab_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised_documentation_en-US" xlink:label="lab_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of stock issued as a result of the exercise of stock options and warrants.</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock_9440d8e0-454c-4842-a72c-c2f754dcde38_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Note Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:to="lab_us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_1fae990d-8279-472b-a949-45a11c7cc3c3_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of stock option activity under Plan</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Option, Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_83556363-50f8-46dd-892c-c81c89029379_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maturities of marketable securities</link:label>
    <link:label id="lab_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_label_en-US" xlink:label="lab_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:to="lab_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalCommonStock_963bb820-e5c6-4614-8a5b-f47720681027_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional paid-in capital</link:label>
    <link:label id="lab_us-gaap_AdditionalPaidInCapitalCommonStock_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalCommonStock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional Paid in Capital, Common Stock</link:label>
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    <link:label id="lab_dei_EntityRegistrantName_749416c5-68eb-4194-9ace-6e2ecade0b3b_terseLabel_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:label id="lab_dei_EntityRegistrantName_label_en-US" xlink:label="lab_dei_EntityRegistrantName" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Registrant Name</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityRegistrantName"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityRegistrantName" xlink:to="lab_dei_EntityRegistrantName" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MarketableSecuritiesAbstract_edd040b3-8e88-4bf6-90cb-bdd11e3f7ff3_terseLabel_en-US" xlink:label="lab_us-gaap_MarketableSecuritiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable Securities [Abstract]</link:label>
    <link:label id="lab_us-gaap_MarketableSecuritiesAbstract_label_en-US" xlink:label="lab_us-gaap_MarketableSecuritiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable Securities [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketableSecuritiesAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MarketableSecuritiesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MarketableSecuritiesAbstract" xlink:to="lab_us-gaap_MarketableSecuritiesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_db537fb5-ec30-4a06-8911-977f69e7a990_terseLabel_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:label id="lab_us-gaap_StatementOfStockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="lab_us-gaap_StatementOfStockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares_a7f39e78-4766-401b-9c53-ba6920c6f900_negatedLabel_en-US" xlink:label="lab_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retirement of common stock in exchange for common stock warrant (in shares)</link:label>
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    <link:label id="lab_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares_documentation_en-US" xlink:label="lab_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of stock that have been retired in exchange for common stock warrant</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares" xlink:href="mrsn-20200930.xsd#mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares" xlink:to="lab_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_6e3cad01-31de-40c7-b7e9-17fe76cf1691_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unamortized issuance costs</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_128c8109-49dc-48eb-bfb4-b2e3ba164f78_negatedLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt financing costs, net of accretion</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsNet_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Issuance Costs, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsNet" xlink:to="lab_us-gaap_DeferredFinanceCostsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8c6fb4bd-75d1-4147-a13a-e89dcbaca46e_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted- Average Exercise&#160;Price</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_cd8051eb-a63c-45d9-9d15-d48bd4296f33_negatedLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Present value adjustment</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_StockIssuanceProgramAuthorizedAmount_cdb8a840-0719-4632-aad7-be2ded9ab210_terseLabel_en-US" xlink:label="lab_mrsn_StockIssuanceProgramAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of shares authorized to be offered and sold</link:label>
    <link:label id="lab_mrsn_StockIssuanceProgramAuthorizedAmount_label_en-US" xlink:label="lab_mrsn_StockIssuanceProgramAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issuance Program, Authorized Amount</link:label>
    <link:label id="lab_mrsn_StockIssuanceProgramAuthorizedAmount_documentation_en-US" xlink:label="lab_mrsn_StockIssuanceProgramAuthorizedAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of common stock shares authorized to be issued under the program.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_StockIssuanceProgramAuthorizedAmount" xlink:href="mrsn-20200930.xsd#mrsn_StockIssuanceProgramAuthorizedAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_StockIssuanceProgramAuthorizedAmount" xlink:to="lab_mrsn_StockIssuanceProgramAuthorizedAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_TenantImprovementAllowance_6372d2af-4c19-42f3-95e8-ada6cbcef8a6_terseLabel_en-US" xlink:label="lab_mrsn_TenantImprovementAllowance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Tenant improvement allowance</link:label>
    <link:label id="lab_mrsn_TenantImprovementAllowance_label_en-US" xlink:label="lab_mrsn_TenantImprovementAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Tenant Improvement Allowance</link:label>
    <link:label id="lab_mrsn_TenantImprovementAllowance_documentation_en-US" xlink:label="lab_mrsn_TenantImprovementAllowance" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of allowance granted and reimbursable by the landlord to a tenant to entice tenant to move into landlord's building which will enable the tenant to prepare the leased premises for tenants occupancy.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_TenantImprovementAllowance" xlink:href="mrsn-20200930.xsd#mrsn_TenantImprovementAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_TenantImprovementAllowance" xlink:to="lab_mrsn_TenantImprovementAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ResearchAndDevelopmentExpenseMember_e4cbc7e4-49c8-4b44-89dd-643d93c15fc2_terseLabel_en-US" xlink:label="lab_us-gaap_ResearchAndDevelopmentExpenseMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Research and development</link:label>
    <link:label id="lab_us-gaap_ResearchAndDevelopmentExpenseMember_label_en-US" xlink:label="lab_us-gaap_ResearchAndDevelopmentExpenseMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Research and Development Expense [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ResearchAndDevelopmentExpenseMember" xlink:to="lab_us-gaap_ResearchAndDevelopmentExpenseMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityIncorporationStateCountryCode_f77ae468-36f3-4b5c-823c-9a25fd5c3ffd_terseLabel_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
    <link:label id="lab_dei_EntityIncorporationStateCountryCode_label_en-US" xlink:label="lab_dei_EntityIncorporationStateCountryCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Incorporation, State or Country Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityIncorporationStateCountryCode" xlink:to="lab_dei_EntityIncorporationStateCountryCode" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_7a8948b1-584c-4402-b17a-7e2f386f7525_totalLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease payments</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SharesIssuedPricePerShare_d93ee4b7-737c-4ca3-abf7-bc1fcf29d5d0_terseLabel_en-US" xlink:label="lab_us-gaap_SharesIssuedPricePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares sold, price per share (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_SharesIssuedPricePerShare_label_en-US" xlink:label="lab_us-gaap_SharesIssuedPricePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares Issued, Price Per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssuedPricePerShare" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesIssuedPricePerShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharesIssuedPricePerShare" xlink:to="lab_us-gaap_SharesIssuedPricePerShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_df326314-e8d8-49a9-bbbd-f117e44db597_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Adjustments for New Accounting Pronouncements [Axis]</link:label>
    <link:label id="lab_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_label_en-US" xlink:label="lab_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Standards Update [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="lab_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock_86ab47fa-7dc4-4184-bb12-2d4b48b7ac4e_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Cash and Cash Equivalents</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Cash and Cash Equivalents [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedCashNoncurrent_5b8fae0d-f33e-4792-86f2-8ae71f1f7738_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCashNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted cash included in other assets</link:label>
    <link:label id="lab_us-gaap_RestrictedCashNoncurrent_label_en-US" xlink:label="lab_us-gaap_RestrictedCashNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Cash, Noncurrent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashNoncurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedCashNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedCashNoncurrent" xlink:to="lab_us-gaap_RestrictedCashNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_7c287470-09d9-45d6-b0b0-6f91784bcfc5_negatedLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross Unrealized Losses</link:label>
    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_label_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:to="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsidiarySaleOfStockAxis_bf8b5fbe-36a7-4a75-9518-ba02414caaaa_terseLabel_en-US" xlink:label="lab_us-gaap_SubsidiarySaleOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sale of Stock [Axis]</link:label>
    <link:label id="lab_us-gaap_SubsidiarySaleOfStockAxis_label_en-US" xlink:label="lab_us-gaap_SubsidiarySaleOfStockAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sale of Stock [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis" xlink:to="lab_us-gaap_SubsidiarySaleOfStockAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressPostalZipCode_39bcb46c-f8af-4cd1-a281-db3ae50d4b7d_terseLabel_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:label id="lab_dei_EntityAddressPostalZipCode_label_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityAddressPostalZipCode"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressPostalZipCode" xlink:to="lab_dei_EntityAddressPostalZipCode" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheFourMember_76d05a5f-0665-4868-a897-65ddee705eec_terseLabel_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheFourMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Four</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheFourMember_label_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheFourMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Four [Member]</link:label>
    <link:label id="lab_mrsn_AmendedCreditFacilityTrancheFourMember_documentation_en-US" xlink:label="lab_mrsn_AmendedCreditFacilityTrancheFourMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amended Credit Facility, Tranche Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_AmendedCreditFacilityTrancheFourMember" xlink:href="mrsn-20200930.xsd#mrsn_AmendedCreditFacilityTrancheFourMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_AmendedCreditFacilityTrancheFourMember" xlink:to="lab_mrsn_AmendedCreditFacilityTrancheFourMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_072a4bb8-03a3-4726-8c0f-7801b8acb675_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale [Line Items]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="lab_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentTransitionReport_4ec58ad3-a11c-4a08-8602-36f4643bd6eb_terseLabel_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Transition Report</link:label>
    <link:label id="lab_dei_DocumentTransitionReport_label_en-US" xlink:label="lab_dei_DocumentTransitionReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Transition Report</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentTransitionReport"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentTransitionReport" xlink:to="lab_dei_DocumentTransitionReport" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty_61c95e36-9927-48f3-a5a7-6a8b3056dad3_terseLabel_en-US" xlink:label="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of biotechnology companies where Company has licensed intellectual property</link:label>
    <link:label id="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty_label_en-US" xlink:label="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of Biotechnology Companies Where Company has Licensed Intellectual Property</link:label>
    <link:label id="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty_documentation_en-US" xlink:label="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents the number of biotechnology companies where Company has licensed intellectual property.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" xlink:href="mrsn-20200930.xsd#mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" xlink:to="lab_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c0a185eb-48b8-45be-9516-d320c884c656_terseLabel_en-US" xlink:label="lab_us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Arrangements and Non-arrangement Transactions [Domain]</link:label>
    <link:label id="lab_us-gaap_ArrangementsAndNonarrangementTransactionsMember_label_en-US" xlink:label="lab_us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangement and Arrangement Other than Collaborative [Domain]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:to="lab_us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets_0f7fb18c-e031-41c4-a3d1-266a22db2f9c_terseLabel_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase in right-of-use asset</link:label>
    <link:label id="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets_label_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease Modification, Increase (Decrease) In Right-of-use Assets</link:label>
    <link:label id="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets_documentation_en-US" xlink:label="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of increase (decrease) in lessee's right to use underlying asset under operating lease due to lease modification</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" xlink:href="mrsn-20200930.xsd#mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" xlink:to="lab_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_2f3cc780-021f-4fad-88fa-86c1891c3b22_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock options</link:label>
    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_label_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="lab_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_WarrantMember_9a9e65f7-ec43-4bea-9e6f-6f1bb6046e69_terseLabel_en-US" xlink:label="lab_us-gaap_WarrantMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrants</link:label>
    <link:label id="lab_us-gaap_WarrantMember_label_en-US" xlink:label="lab_us-gaap_WarrantMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Warrant [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WarrantMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WarrantMember" xlink:to="lab_us-gaap_WarrantMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NonoperatingIncomeExpenseAbstract_9db83f77-2a7e-4667-95fa-130f5136a1dd_terseLabel_en-US" xlink:label="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other income (expense):</link:label>
    <link:label id="lab_us-gaap_NonoperatingIncomeExpenseAbstract_label_en-US" xlink:label="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Nonoperating Income (Expense) [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:to="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued_858b707e-e5d8-43b1-b5f2-92cb58240cc3_terseLabel_en-US" xlink:label="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares into which warrant issued during period may be converted (in shares)</link:label>
    <link:label id="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued_label_en-US" xlink:label="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Warrant or Right, Securities Called by Warrants or Rights, Number Issued</link:label>
    <link:label id="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued_documentation_en-US" xlink:label="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of securities into which the class of warrant or right issued during the period may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" xlink:href="mrsn-20200930.xsd#mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" xlink:to="lab_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueInputsLevel2Member_58bd8100-a924-4d03-b503-95fa17c1c0c8_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Significant Other Observable Inputs (Level 2)</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel2Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Inputs, Level 2 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel2Member" xlink:to="lab_us-gaap_FairValueInputsLevel2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentQuarterlyReport_55980904-68c5-44e9-9dac-25c3a81b4d89_terseLabel_en-US" xlink:label="lab_dei_DocumentQuarterlyReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Quarterly Report</link:label>
    <link:label id="lab_dei_DocumentQuarterlyReport_label_en-US" xlink:label="lab_dei_DocumentQuarterlyReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Quarterly Report</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentQuarterlyReport"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentQuarterlyReport" xlink:to="lab_dei_DocumentQuarterlyReport" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_NumberOfVotesPerCommonShare_56a4cdc6-08ca-43ae-843f-e0033b0b5a07_terseLabel_en-US" xlink:label="lab_mrsn_NumberOfVotesPerCommonShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of votes for each shares held</link:label>
    <link:label id="lab_mrsn_NumberOfVotesPerCommonShare_label_en-US" xlink:label="lab_mrsn_NumberOfVotesPerCommonShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of Votes Per Common Share</link:label>
    <link:label id="lab_mrsn_NumberOfVotesPerCommonShare_documentation_en-US" xlink:label="lab_mrsn_NumberOfVotesPerCommonShare" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents the number of votes for each shares held.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_NumberOfVotesPerCommonShare" xlink:href="mrsn-20200930.xsd#mrsn_NumberOfVotesPerCommonShare"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_NumberOfVotesPerCommonShare" xlink:to="lab_mrsn_NumberOfVotesPerCommonShare" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_c2ff470e-5a30-4aa5-b0ec-86bdfdd185f6_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Class [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Class [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="lab_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpenseMember_08fd45ee-53d9-4ca9-871c-f4c9b93c763c_terseLabel_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpenseMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">General and administrative</link:label>
    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpenseMember_label_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpenseMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">General and Administrative Expense [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GeneralAndAdministrativeExpenseMember" xlink:to="lab_us-gaap_GeneralAndAdministrativeExpenseMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_775e4e34-e3d9-422a-8d92-05127771c39f_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total assets regularly measured and carried at fair value</link:label>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_label_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Fair Value Disclosure</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosure" xlink:to="lab_us-gaap_AssetsFairValueDisclosure" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MaturitiesOfLongTermDebtAbstract_57132e18-cdf3-4c1c-ae13-905e8c1d4dd3_terseLabel_en-US" xlink:label="lab_us-gaap_MaturitiesOfLongTermDebtAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Estimated future principal payments</link:label>
    <link:label id="lab_us-gaap_MaturitiesOfLongTermDebtAbstract_label_en-US" xlink:label="lab_us-gaap_MaturitiesOfLongTermDebtAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maturities of Long-term Debt [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MaturitiesOfLongTermDebtAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MaturitiesOfLongTermDebtAbstract"/>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtDisclosureAbstract_e5a4c0e8-1f6e-43d8-b3d9-c928714da8db_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Disclosure [Abstract]</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureAbstract_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Disclosure [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtDisclosureAbstract" xlink:to="lab_us-gaap_DebtDisclosureAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ContractWithCustomerLiabilityDecrease_0658366f-a448-4fe2-836c-fce42367317d_terseLabel_en-US" xlink:label="lab_mrsn_ContractWithCustomerLiabilityDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred revenue, Deductions</link:label>
    <link:label id="lab_mrsn_ContractWithCustomerLiabilityDecrease_label_en-US" xlink:label="lab_mrsn_ContractWithCustomerLiabilityDecrease" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contract with Customer, Liability, Decrease</link:label>
    <link:label id="lab_mrsn_ContractWithCustomerLiabilityDecrease_documentation_en-US" xlink:label="lab_mrsn_ContractWithCustomerLiabilityDecrease" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of decrease in obligation to transfer good or service to customer for which consideration has been received or is receivable.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ContractWithCustomerLiabilityDecrease" xlink:href="mrsn-20200930.xsd#mrsn_ContractWithCustomerLiabilityDecrease"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ContractWithCustomerLiabilityDecrease" xlink:to="lab_mrsn_ContractWithCustomerLiabilityDecrease" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_d933341c-3d56-4c01-bb5f-3a4737f4ed2d_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash provided by financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition_3179c7ba-b3b7-40d8-abf5-7fbd8a1ddd45_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase of common stock under ESPP</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued_07a16871-8f1e-4107-95a6-371884b3fcda_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Issuance of common stock warrant in exchange for retirement of common stock</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Adjustments to Additional Paid in Capital, Warrant Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross_8cb4d7b7-141a-45d2-b28d-fa5ca1b2d290_terseLabel_en-US" xlink:label="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of options granted in period (in shares)</link:label>
    <link:label id="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross_label_en-US" xlink:label="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangements By Share-based Payment Award, Grants In Period, Gross</link:label>
    <link:label id="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross_documentation_en-US" xlink:label="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The number of grants made during the period for share options (or share units) and for other than stock (or unit) options, including but not limited to, restricted stock options (or units). This amount does not include options granted as part of an inducement award.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" xlink:href="mrsn-20200930.xsd#mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" xlink:to="lab_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_7a248895-b45b-4e51-b373-e9e0c9dfbd57_verboseLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock-based compensation expense included in total operating expenses</link:label>
    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_label_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllocatedShareBasedCompensationExpense" xlink:to="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockValue_239246a0-39c5-4db8-b5f0-184cb2f79e48_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock,$0.0001 par value; 175,000,000 shares authorized; 68,470,081 and 45,388,023&#160;shares issued and outstanding at September&#160;30, 2020 and December&#160;31, 2019, respectively</link:label>
    <link:label id="lab_us-gaap_CommonStockValue_label_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Value, Issued</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockValue" xlink:to="lab_us-gaap_CommonStockValue" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ContractualLifeOfWarrants_697b7e85-2149-4da1-9a37-b800c2eb1bab_terseLabel_en-US" xlink:label="lab_mrsn_ContractualLifeOfWarrants" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contractual life of warrants</link:label>
    <link:label id="lab_mrsn_ContractualLifeOfWarrants_label_en-US" xlink:label="lab_mrsn_ContractualLifeOfWarrants" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contractual Life of Warrants</link:label>
    <link:label id="lab_mrsn_ContractualLifeOfWarrants_documentation_en-US" xlink:label="lab_mrsn_ContractualLifeOfWarrants" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The contractual life of warrants.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ContractualLifeOfWarrants" xlink:href="mrsn-20200930.xsd#mrsn_ContractualLifeOfWarrants"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ContractualLifeOfWarrants" xlink:to="lab_mrsn_ContractualLifeOfWarrants" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentFiscalYearFocus_c4715782-b12c-4684-9337-4607f0fa592c_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Year Focus</link:label>
    <link:label id="lab_dei_DocumentFiscalYearFocus_label_en-US" xlink:label="lab_dei_DocumentFiscalYearFocus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Year Focus</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_DocumentFiscalYearFocus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalYearFocus" xlink:to="lab_dei_DocumentFiscalYearFocus" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LongTermDebtCurrent_5a081095-29de-4a0c-8395-50c2f46281b1_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term debt</link:label>
    <link:label id="lab_us-gaap_LongTermDebtCurrent_label_en-US" xlink:label="lab_us-gaap_LongTermDebtCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Current Maturities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtCurrent" xlink:to="lab_us-gaap_LongTermDebtCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCurrentReportingStatus_240881bb-316d-4489-840b-7ee1d9a81474_terseLabel_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Current Reporting Status</link:label>
    <link:label id="lab_dei_EntityCurrentReportingStatus_label_en-US" xlink:label="lab_dei_EntityCurrentReportingStatus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Current Reporting Status</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityCurrentReportingStatus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCurrentReportingStatus" xlink:to="lab_dei_EntityCurrentReportingStatus" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsequentEventTable_4e0956aa-c77c-4467-bbdd-7eb91cecbde6_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Subsequent Event [Table]</link:label>
    <link:label id="lab_us-gaap_SubsequentEventTable_label_en-US" xlink:label="lab_us-gaap_SubsequentEventTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Subsequent Event [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTable" xlink:to="lab_us-gaap_SubsequentEventTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_6486e6d5-39c5-4777-9e10-b76b251b6bb2_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase of marketable securities</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments to Acquire Debt Securities, Available-for-sale</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:to="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_cedecdf4-936f-40f6-825d-0893f75e3c33_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Loss per Share</link:label>
    <link:label id="lab_us-gaap_EarningsPerSharePolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="lab_us-gaap_EarningsPerSharePolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentTable_e9c2a162-2707-4949-a6fe-4f72793eb482_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTable_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable"/>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_1f276aed-bba6-40bd-a7ee-c8781ceef590_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash flows from investing activities</link:label>
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    <link:label id="lab_us-gaap_CommonStockSharesIssued_c2862f0e-9b1c-4b3f-9a45-752463961658_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesIssued" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock, shares issued (in shares)</link:label>
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    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_d3edd6c4-c4a3-4bce-bf41-381caeaf0ff8_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and Cash Equivalents, at Carrying Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
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    <link:label id="lab_us-gaap_RevenueFromContractWithCustomerProductAndServiceExtensibleList_0ab3eb4a-9856-409a-999e-ec2ee170f07f_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerProductAndServiceExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Type of revenue [Extensible List]</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseLiability_9f50271c-008c-4919-818f-505f00c98ae9_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Present value of lease liabilities</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiability_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiability" xlink:to="lab_us-gaap_OperatingLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_2301d155-b486-4e22-bc2a-712175260813_terseLabel_en-US" xlink:label="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable"/>
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    <link:label id="lab_us-gaap_LongTermDebtNoncurrent_1ff07c7e-15b1-47d3-943c-de50275586d6_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term debt, net</link:label>
    <link:label id="lab_us-gaap_LongTermDebtNoncurrent_label_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Excluding Current Maturities</link:label>
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    <link:label id="lab_us-gaap_SubstantialDoubtAboutGoingConcernWithinOneYear_9ebcc5af-e0ce-4859-a07b-892a02638cf3_terseLabel_en-US" xlink:label="lab_us-gaap_SubstantialDoubtAboutGoingConcernWithinOneYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Substantial doubt about going concern, within twelve months</link:label>
    <link:label id="lab_us-gaap_SubstantialDoubtAboutGoingConcernWithinOneYear_label_en-US" xlink:label="lab_us-gaap_SubstantialDoubtAboutGoingConcernWithinOneYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Substantial Doubt about Going Concern, within One Year [true false]</link:label>
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    <link:label id="lab_mrsn_ProceedsFromDebtNetIssuanceCosts_a098b05c-7378-4371-87c4-835c98b1f9e1_terseLabel_en-US" xlink:label="lab_mrsn_ProceedsFromDebtNetIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from issuance of debt, net of issuance costs</link:label>
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    <link:label id="lab_mrsn_ProceedsFromDebtNetIssuanceCosts_documentation_en-US" xlink:label="lab_mrsn_ProceedsFromDebtNetIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The cash inflow (outflow) during the period from borrowings in aggregate debt. Includes proceeds from short-term and long-term debt and delayed cash payments of issuance costs.</link:label>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_616354b7-473c-41ab-9808-4dd55b1d82ee_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounts receivable</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentLineItems_ce080d95-20c0-46b4-a0e4-2ff7be6982f0_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentLineItems" xlink:to="lab_us-gaap_DebtInstrumentLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquity_92bcec23-b7d6-459f-bbaf-e54997d688c6_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total stockholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_6bf35018-0d93-44f8-96f2-1d86374c920c_periodStartLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance at beginning of period</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_baa2d1b4-8ff1-4ce1-8b56-bac48bfebd97_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance at end of period</link:label>
    <link:label id="lab_us-gaap_StockholdersEquity_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Attributable to Parent</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="lab_us-gaap_StockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_StockIncentivePlan2017Member_597c366d-1e42-4b95-bfd2-ff509e7ba863_terseLabel_en-US" xlink:label="lab_mrsn_StockIncentivePlan2017Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2017 Plan</link:label>
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    <link:label id="lab_mrsn_StockIncentivePlan2017Member_documentation_en-US" xlink:label="lab_mrsn_StockIncentivePlan2017Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents information pertaining to 2017 Stock incentive plan.</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_2058f02c-06e9-4b82-a4e1-3d19aa7f1ec8_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total liabilities and stockholders&#8217; equity</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_ced560e7-8247-470b-8c3b-df3ac4c91173_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated other comprehensive income (loss)</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:to="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressCityOrTown_f6b4e0c0-4876-49be-b96b-543b8a7e48cd_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:label id="lab_dei_EntityAddressCityOrTown_label_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressCityOrTown" xlink:to="lab_dei_EntityAddressCityOrTown" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_ad12656d-1426-4897-ab5d-3224f2ded3ae_terseLabel_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued payroll and related expenses</link:label>
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee-related Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:to="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_8331d27c-9afd-4055-9ae1-afd809aaeb93_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_7889c3df-c28f-426e-88b2-f0468a2c394f_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted stock units</link:label>
    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_label_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Stock Units (RSUs) [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
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    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_0f81dcae-3bfc-4cb7-946d-79a62733263a_terseLabel_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">General and administrative</link:label>
    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_label_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">General and Administrative Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GeneralAndAdministrativeExpense" xlink:to="lab_us-gaap_GeneralAndAdministrativeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinancialInstrumentAxis_592fb27d-1dec-4fe8-a8b4-39ae998cef5c_terseLabel_en-US" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financial Instrument [Axis]</link:label>
    <link:label id="lab_us-gaap_FinancialInstrumentAxis_label_en-US" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financial Instrument [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancialInstrumentAxis" xlink:to="lab_us-gaap_FinancialInstrumentAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TypeOfAdoptionMember_8e62e388-7b36-47f3-9f40-b781fa0766fc_terseLabel_en-US" xlink:label="lab_us-gaap_TypeOfAdoptionMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Type of Adoption [Domain]</link:label>
    <link:label id="lab_us-gaap_TypeOfAdoptionMember_label_en-US" xlink:label="lab_us-gaap_TypeOfAdoptionMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Standards Update [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TypeOfAdoptionMember" xlink:to="lab_us-gaap_TypeOfAdoptionMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_b37183bd-7029-40b6-be6f-d36e8c2627fd_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Anti-dilutive securities (in shares)</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:to="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_630414fe-ad5d-442f-b627-c61c8878202a_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other non-cash items</link:label>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_label_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Noncash Income (Expense)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNoncashIncomeExpense" xlink:to="lab_us-gaap_OtherNoncashIncomeExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityExTransitionPeriod_b470991c-c76f-43c9-8a76-6102f7feb592_terseLabel_en-US" xlink:label="lab_dei_EntityExTransitionPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Ex Transition Period</link:label>
    <link:label id="lab_dei_EntityExTransitionPeriod_label_en-US" xlink:label="lab_dei_EntityExTransitionPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Ex Transition Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityExTransitionPeriod" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityExTransitionPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityExTransitionPeriod" xlink:to="lab_dei_EntityExTransitionPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityComponentDomain_4b73d335-50a7-43a3-8d20-69164101fe73_terseLabel_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:label id="lab_us-gaap_EquityComponentDomain_label_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityComponentDomain" xlink:to="lab_us-gaap_EquityComponentDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense_86f6bc61-48d2-429b-88ac-e94025471e19_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of additional fees receivable when target is designated and commercial license to target is granted</link:label>
    <link:label id="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense_label_en-US" xlink:label="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaboration Arrangements, Additional Payment to Obtain a Development and Commercial License</link:label>
    <link:label id="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense_documentation_en-US" xlink:label="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of additional fees receivable when a target is designated and the commercial license to the target is granted under terms of the agreement.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" xlink:href="mrsn-20200930.xsd#mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" xlink:to="lab_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_ff7fa520-047c-4a8c-87b2-d8347e5125cc_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property and equipment, net</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityTaxIdentificationNumber_b2043b4f-5db6-4f17-8094-69e38ddeed9e_terseLabel_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Tax Identification Number</link:label>
    <link:label id="lab_dei_EntityTaxIdentificationNumber_label_en-US" xlink:label="lab_dei_EntityTaxIdentificationNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Tax Identification Number</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityTaxIdentificationNumber" xlink:to="lab_dei_EntityTaxIdentificationNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour_a4f68e87-8d95-4064-b880-0461f035b9a4_terseLabel_en-US" xlink:label="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2024 and thereafter</link:label>
    <link:label id="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour_label_en-US" xlink:label="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Payments, Due Year Four And After Year Four</link:label>
    <link:label id="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour_documentation_en-US" xlink:label="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of lessee's undiscounted obligation for lease payments for finance lease, due year four and after fourth fiscal year following current fiscal year.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:href="mrsn-20200930.xsd#mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:to="lab_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_19a7457d-6b42-403a-a87c-c4d31435e179_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock options</link:label>
    <link:label id="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_label_en-US" xlink:label="lab_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement [Text Block]</link:label>
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    <link:label id="lab_us-gaap_NetIncomeLoss_fb6d0bf3-54c7-4feb-a09c-4ff1c0366ef1_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_a4bf5657-9694-4779-ad14-cce37ae69c3a_verboseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net (loss) income</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_dc29cdca-2bb5-40ee-b4c0-97f023268de5_negatedLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_label_en-US" xlink:label="lab_us-gaap_NetIncomeLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income (Loss) Attributable to Parent</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="lab_us-gaap_NetIncomeLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_25bfeb95-a67e-49b7-964c-5d2904124e01_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Changes in operating assets and liabilities:</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Operating Capital [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherLiabilitiesCurrent_d1679b30-cb16-4295-b0a8-0c05996107a3_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other liabilities</link:label>
    <link:label id="lab_us-gaap_OtherLiabilitiesCurrent_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Liabilities, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_9bc9fb77-12da-46d1-90fc-24ee931a192c_terseLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Marketable securities</link:label>
    <link:label id="lab_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_label_en-US" xlink:label="lab_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract" xlink:to="lab_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_90662bd5-2072-4e08-83ae-5e529a3ed72f_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2020 (excluding the nine months ended September 30, 2020)</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_3f9a94cb-fa7e-436b-9d7b-bd580866cfb4_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other comprehensive income (loss)</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedPremium_fff8d42a-c979-4cdf-8153-c4b25cd7d40a_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedPremium" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accretion related to final payment</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedPremium_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedPremium" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument, Unamortized Premium</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedPremium" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentUnamortizedPremium"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentUnamortizedPremium" xlink:to="lab_us-gaap_DebtInstrumentUnamortizedPremium" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_DebtCovenantPeriodAxis_0499770c-55db-4e97-93b7-4d729766db52_terseLabel_en-US" xlink:label="lab_mrsn_DebtCovenantPeriodAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Covenant, Period [Axis]</link:label>
    <link:label id="lab_mrsn_DebtCovenantPeriodAxis_label_en-US" xlink:label="lab_mrsn_DebtCovenantPeriodAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Covenant, Period [Axis]</link:label>
    <link:label id="lab_mrsn_DebtCovenantPeriodAxis_documentation_en-US" xlink:label="lab_mrsn_DebtCovenantPeriodAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Covenant, Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_DebtCovenantPeriodAxis" xlink:href="mrsn-20200930.xsd#mrsn_DebtCovenantPeriodAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_DebtCovenantPeriodAxis" xlink:to="lab_mrsn_DebtCovenantPeriodAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeasesAbstract_1207dfac-b0f1-43c2-b63c-42e2146a94af_terseLabel_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases [Abstract]</link:label>
    <link:label id="lab_us-gaap_LeasesAbstract_label_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeasesAbstract" xlink:to="lab_us-gaap_LeasesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsCurrent_b4af6c4d-d756-4090-8103-65996f057782_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total current assets</link:label>
    <link:label id="lab_us-gaap_AssetsCurrent_label_en-US" xlink:label="lab_us-gaap_AssetsCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="lab_us-gaap_AssetsCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_3fccb684-2c6c-452d-a445-69d8bcd62e1e_terseLabel_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:label id="lab_dei_CurrentFiscalYearEndDate_label_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CurrentFiscalYearEndDate" xlink:to="lab_dei_CurrentFiscalYearEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_SupplyAgreementMerckKgaaMember_41b93479-6330-4676-8bb3-6e67e3d7558e_terseLabel_en-US" xlink:label="lab_mrsn_SupplyAgreementMerckKgaaMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Merck KGaA Supply Agreement</link:label>
    <link:label id="lab_mrsn_SupplyAgreementMerckKgaaMember_label_en-US" xlink:label="lab_mrsn_SupplyAgreementMerckKgaaMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supply Agreement Merck Kgaa [Member]</link:label>
    <link:label id="lab_mrsn_SupplyAgreementMerckKgaaMember_documentation_en-US" xlink:label="lab_mrsn_SupplyAgreementMerckKgaaMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents information pertaining to the Supply Agreement with Merck KGaA.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_SupplyAgreementMerckKgaaMember" xlink:href="mrsn-20200930.xsd#mrsn_SupplyAgreementMerckKgaaMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_SupplyAgreementMerckKgaaMember" xlink:to="lab_mrsn_SupplyAgreementMerckKgaaMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingExpensesAbstract_4dce984c-72aa-4af4-a05f-32c705a4e4ba_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating expenses:</link:label>
    <link:label id="lab_us-gaap_OperatingExpensesAbstract_label_en-US" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Expenses [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingExpensesAbstract" xlink:to="lab_us-gaap_OperatingExpensesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiability_69bffc9d-a8d1-45a2-be8e-077d7586feb5_verboseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total finance lease liability</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiability_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiability" xlink:to="lab_us-gaap_FinanceLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_dbc4a613-25a7-4baf-a776-9d01d54e9f11_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Anti-dilutive securities</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_bafa872c-608a-4a62-97c2-30f6327e615f_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' equity:</link:label>
    <link:label id="lab_us-gaap_StockholdersEquityAbstract_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stockholders' Equity Attributable to Parent [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityAbstract" xlink:to="lab_us-gaap_StockholdersEquityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_582dca8a-054f-4cd0-a4f6-b09d74d42f86_terseLabel_en-US" xlink:label="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of shares of common stock into which warrants may be converted</link:label>
    <link:label id="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_label_en-US" xlink:label="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Class of Warrant or Right, Number of Securities Called by Warrants or Rights</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:to="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_8badc4d5-dcaf-45d8-b912-6dd7ea83345e_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of&#160;Shares</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentFiscalPeriodFocus_bedfae35-cd3d-48a4-a268-678522c10cbd_terseLabel_en-US" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Fiscal Period Focus</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalPeriodFocus" xlink:to="lab_dei_DocumentFiscalPeriodFocus" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SubsidiarySaleOfStockLineItems_4c506515-c9a3-4e21-9952-059d768c61c4_verboseLabel_en-US" xlink:label="lab_us-gaap_SubsidiarySaleOfStockLineItems" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Offering program</link:label>
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    <link:label id="lab_mrsn_LeasesLineItems_205420e1-51bf-434a-8d11-d73106f3d8b4_terseLabel_en-US" xlink:label="lab_mrsn_LeasesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases</link:label>
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    <link:label id="lab_mrsn_LeasesLineItems_documentation_en-US" xlink:label="lab_mrsn_LeasesLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</link:label>
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    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_3773ce84-491f-4bdd-bb57-34a3b7d8338f_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income (loss) attributable to common stockholders - diluted</link:label>
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    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_702e89b1-a43f-46d3-9354-4c82b1cd7375_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental disclosures of non-cash activities:</link:label>
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    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_005e665a-d6eb-411c-8f5b-b11553195dbd_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase of common stock under ESPP (in shares)</link:label>
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    <link:label id="lab_dei_EntityFilerCategory_de730b5c-29ef-49f6-a766-d7f7999b0d52_terseLabel_en-US" xlink:label="lab_dei_EntityFilerCategory" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Filer Category</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_ed52b3e2-5a53-4d01-9e52-8165b67dab31_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of stock-based compensation expense as reflected in the Company&#8217;s condensed consolidated statements of operations and comprehensive loss</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_CommonStockMember_8b131041-2fdc-4a39-a1e2-602c59171ae1_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common&#160;Stock</link:label>
    <link:label id="lab_us-gaap_CommonStockMember_label_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock [Member]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockMember" xlink:to="lab_us-gaap_CommonStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductsAndServicesDomain_874c8ca4-3f83-47d2-a4d9-d379dfef9800_terseLabel_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Products and Services [Domain]</link:label>
    <link:label id="lab_srt_ProductsAndServicesDomain_label_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductsAndServicesDomain" xlink:to="lab_srt_ProductsAndServicesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_ef4b4000-ba06-4774-9024-9cfe3e3f4d7a_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-Lived Tangible Asset [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated_3462a025-a5b2-4cdd-8d0f-c9f17eb6c823_terseLabel_en-US" xlink:label="lab_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of research and development fees expected to be received</link:label>
    <link:label id="lab_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated_label_en-US" xlink:label="lab_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reimbursable Expense, Research and Development, Estimated</link:label>
    <link:label id="lab_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated_documentation_en-US" xlink:label="lab_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Estimated amount of research and development expenses received or expected to be received included in transaction price (performance obligation).</link:label>
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    <link:label id="lab_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction_c45cfa16-dc2a-4e6d-bb48-3196e53813ff_terseLabel_en-US" xlink:label="lab_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt financing costs in accrued expenses</link:label>
    <link:label id="lab_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction_label_en-US" xlink:label="lab_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction</link:label>
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    <link:label id="lab_us-gaap_OtherCommitmentsAxis_label_en-US" xlink:label="lab_us-gaap_OtherCommitmentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Commitments [Axis]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCommitmentsAxis" xlink:to="lab_us-gaap_OtherCommitmentsAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCommitmentsDomain_dad53414-6c21-4c58-9f98-40f574c33db2_terseLabel_en-US" xlink:label="lab_us-gaap_OtherCommitmentsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Commitments [Domain]</link:label>
    <link:label id="lab_us-gaap_OtherCommitmentsDomain_label_en-US" xlink:label="lab_us-gaap_OtherCommitmentsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Commitments [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCommitmentsDomain" xlink:to="lab_us-gaap_OtherCommitmentsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_USTreasurySecuritiesMember_62345985-c034-406b-8dac-c39a2bd5370d_terseLabel_en-US" xlink:label="lab_us-gaap_USTreasurySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">U.S. Treasuries</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasurySecuritiesMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember"/>
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    <link:label id="lab_mrsn_CollaborationArrangementsTargetsDesignatedNumber_1ea1511e-a375-45fe-b05e-0e9201a30f15_terseLabel_en-US" xlink:label="lab_mrsn_CollaborationArrangementsTargetsDesignatedNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Number of targets designated</link:label>
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    <link:label id="lab_us-gaap_InterestPaidNet_ffaff619-f45c-427c-8e31-66affecc9666_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash paid for interest</link:label>
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    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_e4f611d8-32a2-4013-aa22-2f39a3faf839_verboseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Right-of-use assets obtained in exchange for operating lease liabilities</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear_abdc5686-888f-4752-94c9-bc0dc004e92c_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2020 (excluding the three months ended June 30, 2020)</link:label>
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    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_7bcd6847-4331-4b2e-8d86-a9fc763fb644_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and Cash Equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
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    <link:label id="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_9837da5e-3337-4398-8866-9b02d2b1a516_periodStartLabel_en-US" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash, cash equivalents and restricted cash, beginning of period</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_AccruedPreclinicalAndClinicalExpensesCurrent_e79b2a9f-b60d-4e83-b760-c56ef3c95c51_terseLabel_en-US" xlink:label="lab_mrsn_AccruedPreclinicalAndClinicalExpensesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued preclinical, manufacturing and clinical expenses</link:label>
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    <link:label id="lab_mrsn_AccruedPreclinicalAndClinicalExpensesCurrent_documentation_en-US" xlink:label="lab_mrsn_AccruedPreclinicalAndClinicalExpensesCurrent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Carrying value as of the balance sheet date of obligations incurred through that date and payable for preclinical, manufacturing and clinical expense. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_f0b119a5-073e-4857-aab1-b597075b78af_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of estimated future payments</link:label>
    <link:label id="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Maturities of Long-term Debt [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_DebtSecuritiesAvailableForSaleTable_8b9bc3b3-b025-4ff7-a3de-204cb9af4f89_terseLabel_en-US" xlink:label="lab_us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale [Table]</link:label>
    <link:label id="lab_us-gaap_DebtSecuritiesAvailableForSaleTable_label_en-US" xlink:label="lab_us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:to="lab_us-gaap_DebtSecuritiesAvailableForSaleTable" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_56ee0b4d-3fdb-40f7-a5b2-ba9d6b4632e7_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_9bfb3907-9693-4e2c-b088-4bff8f920a71_totalLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:to="lab_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_LocalPhoneNumber_978f081e-2bbc-4fe0-8737-d19b3d7833d2_terseLabel_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Local Phone Number</link:label>
    <link:label id="lab_dei_LocalPhoneNumber_label_en-US" xlink:label="lab_dei_LocalPhoneNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Local Phone Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LocalPhoneNumber"/>
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    <link:label id="lab_us-gaap_TypeOfArrangementAxis_468dbf08-4044-4daf-8d0c-ff1ac1f35458_terseLabel_en-US" xlink:label="lab_us-gaap_TypeOfArrangementAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangement and Arrangement Other than Collaborative [Axis]</link:label>
    <link:label id="lab_us-gaap_TypeOfArrangementAxis_label_en-US" xlink:label="lab_us-gaap_TypeOfArrangementAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collaborative Arrangement and Arrangement Other than Collaborative [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
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    <link:label id="lab_us-gaap_ScheduleOfStockByClassTable_bb7639a0-29d8-499f-8b56-55233433be7a_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfStockByClassTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Stock by Class [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfStockByClassTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfStockByClassTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Stock by Class [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable" xlink:to="lab_us-gaap_ScheduleOfStockByClassTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfDebtTableTextBlock_011a337f-d9e8-4195-b4d9-a5b1e3907296_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of debt</link:label>
    <link:label id="lab_us-gaap_ScheduleOfDebtTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Debt [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDebtTableTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfDebtTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfDebtTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfDebtTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_e06e35b9-eea0-439b-b475-1345afa7b749_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Outstanding debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_cf7e5394-ebf1-4a7f-832e-09d43d23b347_totalLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Gross</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:to="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressAddressLine1_125f4e1d-8d95-4f25-b1f1-c31622d20f75_terseLabel_en-US" xlink:label="lab_dei_EntityAddressAddressLine1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Address Line One</link:label>
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    <link:label id="lab_us-gaap_RestrictedCashAndInvestmentsAbstract_503bc6ef-fdaa-4085-8e3e-4634d72adabd_verboseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCashAndInvestmentsAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Assets</link:label>
    <link:label id="lab_us-gaap_RestrictedCashAndInvestmentsAbstract_label_en-US" xlink:label="lab_us-gaap_RestrictedCashAndInvestmentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Cash and Investments [Abstract]</link:label>
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    <link:label id="lab_us-gaap_PrimeRateMember_3ec29db4-3048-4e72-9fe0-4c5fee2f5d25_terseLabel_en-US" xlink:label="lab_us-gaap_PrimeRateMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Prime Rate</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrimeRateMember" xlink:to="lab_us-gaap_PrimeRateMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract_2033071f-8e46-49b4-b853-b374d0515a1b_terseLabel_en-US" xlink:label="lab_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue recognized in the period from:</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract" xlink:to="lab_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ContractWithCustomerLiability_51d4e921-7530-4930-8b39-89309e7e62f0_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred revenue</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerLiability_a35aa9ca-6582-44a1-b7ff-696396e3a25d_periodStartLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred revenue, Balance at Beginning of Period</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerLiability_bc17dd4f-8e1d-4558-8bfc-18a102cef8ff_periodEndLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred revenue, Balance at End of Period</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerLiability_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contract with Customer, Liability</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ContractWithCustomerLiability" xlink:to="lab_us-gaap_ContractWithCustomerLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ExistingCreditFacilityMember_d9b43a3d-9666-4c80-b6e2-57394a6009bf_terseLabel_en-US" xlink:label="lab_mrsn_ExistingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Existing Credit Facility</link:label>
    <link:label id="lab_mrsn_ExistingCreditFacilityMember_label_en-US" xlink:label="lab_mrsn_ExistingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Existing Credit Facility [Member]</link:label>
    <link:label id="lab_mrsn_ExistingCreditFacilityMember_documentation_en-US" xlink:label="lab_mrsn_ExistingCreditFacilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Existing Credit Facility</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ExistingCreditFacilityMember" xlink:href="mrsn-20200930.xsd#mrsn_ExistingCreditFacilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_ExistingCreditFacilityMember" xlink:to="lab_mrsn_ExistingCreditFacilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_8d3e044c-73a2-49b8-bf60-5e69b76c7c13_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Other Operating Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityEmergingGrowthCompany_12fba474-9a49-4814-819f-68903e85f255_terseLabel_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Emerging Growth Company</link:label>
    <link:label id="lab_dei_EntityEmergingGrowthCompany_label_en-US" xlink:label="lab_dei_EntityEmergingGrowthCompany" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Emerging Growth Company</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityEmergingGrowthCompany" xlink:to="lab_dei_EntityEmergingGrowthCompany" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_b3bc3bf1-c0a2-443c-bd1d-23913a5e6b24_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercise of stock options</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issued During Period, Value, Stock Options Exercised</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_e7e344e8-2c90-4936-918b-d47c76a8ac4d_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum borrowing capacity</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AwardTypeAxis_1e51f82f-0d62-480e-87ff-32963ce8f435_terseLabel_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:label id="lab_us-gaap_AwardTypeAxis_label_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Award Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AwardTypeAxis" xlink:to="lab_us-gaap_AwardTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_MaximumMember_7b02afdf-953e-4eb7-a46d-be4c4fdfac25_terseLabel_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum</link:label>
    <link:label id="lab_srt_MaximumMember_label_en-US" xlink:label="lab_srt_MaximumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_MaximumMember" xlink:to="lab_srt_MaximumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockSharesAuthorized_4acf529f-1922-4658-907d-d517633916d4_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, shares authorized (in shares)</link:label>
    <link:label id="lab_us-gaap_PreferredStockSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_PreferredStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Shares Authorized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockSharesAuthorized" xlink:to="lab_us-gaap_PreferredStockSharesAuthorized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueMeasurementInputsDisclosureTextBlock_d34c8de8-cb3a-474c-836b-2a61191a8d57_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementInputsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value measurements</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementInputsDisclosureTextBlock" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementInputsDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementInputsDisclosureTextBlock" xlink:to="lab_us-gaap_FairValueMeasurementInputsDisclosureTextBlock" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_PreferredStockSharesOutstanding_8f8097b7-8f6e-42d0-9dde-609fd04b8534_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, shares outstanding (in shares)</link:label>
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    <link:label id="lab_mrsn_InducementAwardProgramMember_72c11a0b-b47e-4001-9e33-05df0d064173_terseLabel_en-US" xlink:label="lab_mrsn_InducementAwardProgramMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inducement Award Program</link:label>
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    <link:label id="lab_mrsn_InducementAwardProgramMember_documentation_en-US" xlink:label="lab_mrsn_InducementAwardProgramMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Inducement Award Program</link:label>
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    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_9da885fc-272a-4658-af78-d8c50fb01649_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value measurements</link:label>
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    <link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_5ef9955c-1337-4de4-a351-a7df0cc8a7d2_terseLabel_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Summary of Significant Accounting Policies</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_ea88620b-7e10-4752-887e-578e6f87f491_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash provided by (used in) investing activities</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_f73bd571-c865-4dd9-8447-7bcb3160c81c_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional Disclosures</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73cd0a77-2fa5-4e22-a88d-9ff2c44d5790_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_90f2f4b7-36b8-4562-8615-fea5d424ce96_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Award [Domain]</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Award Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CorporateDebtSecuritiesMember_7f1bc6b5-e494-4cfd-b331-c1d536791dc8_terseLabel_en-US" xlink:label="lab_us-gaap_CorporateDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Corporate bonds</link:label>
    <link:label id="lab_us-gaap_CorporateDebtSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_CorporateDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Corporate Debt Securities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CorporateDebtSecuritiesMember" xlink:to="lab_us-gaap_CorporateDebtSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_TradingSymbol_f1b9da8c-7795-46cc-8a0c-d63dbaed0d8a_terseLabel_en-US" xlink:label="lab_dei_TradingSymbol" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Trading Symbol</link:label>
    <link:label id="lab_dei_TradingSymbol_label_en-US" xlink:label="lab_dei_TradingSymbol" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Trading Symbol</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_TradingSymbol"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_TradingSymbol" xlink:to="lab_dei_TradingSymbol" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_2bbe9d60-8ba7-40ef-97bf-2efaaf699ff1_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Options exercisable, at end of period (in dollars per share)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit_78ded004-1424-45bb-a010-09f7add874a4_terseLabel_en-US" xlink:label="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of credit, increase limit</link:label>
    <link:label id="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit_label_en-US" xlink:label="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line Of Credit Facility, Accordian Feature, Increase Limit</link:label>
    <link:label id="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit_documentation_en-US" xlink:label="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line Of Credit Facility, Accordian Feature, Increase Limit</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit" xlink:href="mrsn-20200930.xsd#mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit" xlink:to="lab_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit" xlink:type="arc" order="1"/>
    <link:label id="lab_mrsn_ExchangeWarrantsMember_01c60e96-804c-425a-8dc9-7a2b6f282b28_terseLabel_en-US" xlink:label="lab_mrsn_ExchangeWarrantsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exchange warrants</link:label>
    <link:label id="lab_mrsn_ExchangeWarrantsMember_label_en-US" xlink:label="lab_mrsn_ExchangeWarrantsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exchange Warrants [Member]</link:label>
    <link:label id="lab_mrsn_ExchangeWarrantsMember_documentation_en-US" xlink:label="lab_mrsn_ExchangeWarrantsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exchange Warrants</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_mrsn_ExchangeWarrantsMember" xlink:href="mrsn-20200930.xsd#mrsn_ExchangeWarrantsMember"/>
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    <link:label id="lab_us-gaap_ContractWithCustomerAssetNet_dd13f2cd-dbe3-4825-8bc3-9d1088b863b6_terseLabel_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contract assets</link:label>
    <link:label id="lab_us-gaap_ContractWithCustomerAssetNet_label_en-US" xlink:label="lab_us-gaap_ContractWithCustomerAssetNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contract with Customer, Asset, after Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerAssetNet"/>
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The Company&#x2019;s innovative platforms, which include Dolaflexin and Dolasynthen, each delivering its DolaLock payload, as well as Immunosynthen, delivering a novel stimulator of interferon genes (STING) agonist, provide an efficient product engine that has enabled a robust discovery pipeline for the Company and its partners. The Company&#x2019;s product candidates include XMT-1536 and XMT-1592. The Company's early stage programs include a potentially first-in-class B7-H4-targeted DolaLock ADC as well as candidates leveraging the Immunosynthen platform. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;XMT-1536, an ADC utilizing the Company&#x2019;s Dolaflexin platform and targeting NaPi2b, an antigen broadly expressed in ovarian cancer and non-small cell lung cancer (NSCLC) adenocarcinoma, is currently in the expansion portion of a Phase 1 study in patients with ovarian cancer and NSCLC adenocarcinoma. XMT-1592 uses one of the Company&#x2019;s new platforms, Dolasynthen, and also targets NaPi2b. The Company filed an Investigational New Drug (IND) application in the first quarter of 2020 and initiated the Phase 1 dose escalation study of XMT-1592 in the second quarter of 2020.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company has incurred cumulative net losses since inception. For the nine months ended September&#160;30, 2020, the net loss was $59,203, compared to net loss of $11,962 in the nine months ended September&#160;30, 2019. The difference year over year is primarily attributable to $39,965 in deferred revenue that was recognized in the first quarter of 2019 as a result of the discontinuation of the partnership with Takeda in that quarter. The Company expects to continue to incur operating losses for at least the next several years. As of September&#160;30, 2020, the Company had an accumulated deficit of $251,575. The future success of the Company is dependent on, among other factors, its ability to identify and develop its product candidates and ultimately upon its ability to attain profitable operations. The Company has devoted substantially all of its financial resources and efforts to research and development and general and administrative expense to support such research and development. Net losses and negative operating cash flows have had, and will continue to have, an adverse effect on the Company&#x2019;s stockholders' equity and working&#160;capital.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In April 2020, the Company sold 10,900,599 shares of common stock and received net proceeds of $62,976. In addition, in June 2020, the Company sold 9,200,000 shares of common stock and received net proceeds of $163,991. The Company believes that its currently available funds will be sufficient to fund the Company&#x2019;s operations through at least the next twelve months from the issuance of this Quarterly Report on Form 10-Q. Management&#x2019;s belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management&#x2019;s estimates, the Company may need to seek additional funding.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, the need for additional capital, risks of failure of preclinical and clinical studies, the need to obtain marketing approval and reimbursement for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development of technological innovations by competitors, reliance on third party manufacturers and the ability to transition from pilot-scale production to large-scale manufacturing of products.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company&#x2019;s unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S.&#160;GAAP) and the rules and regulations of the Securities and Exchange Commission (SEC). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Updates (ASU) of the Financial Accounting Standards Board (FASB). All dollar amounts, except per share data in the text and tables herein, are stated in thousands unless otherwise indicated. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December&#160;31, 2019 and the notes thereto, included in the Company&#x2019;s Annual Report on Form 10-K for the year ended December&#160;31, 2019 filed with the SEC on February 28, 2020.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements. In the opinion of the Company&#x2019;s management, the accompanying unaudited condensed consolidated financial statements contain all adjustments that are necessary to present fairly the Company&#x2019;s financial position as of September&#160;30, 2020, the results of its operations for the three and nine months ended September&#160;30, 2020 and 2019, a statement of stockholders&#x2019; equity for the three and nine months ended September&#160;30, 2020 and 2019 and cash flows for the nine months ended September&#160;30, 2020 and 2019. Such adjustments are of a normal and recurring nature. The results for the three and nine months ended September&#160;30, 2020 are not necessarily indicative of the results for the year ending December&#160;31, 2020, or for any future period.&lt;/span&gt;&lt;/div&gt;</us-gaap:BusinessDescriptionAndBasisOfPresentationTextBlock>
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All intercompany balances and transactions have been eliminated.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Use of Estimates&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The preparation of the Company&#x2019;s unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company&#x2019;s management evaluates its estimates which include, but are not limited to, management&#x2019;s judgments with respect to the identification of performance obligations and standalone selling prices of those performance obligations within its revenue arrangements, accrued expenses, valuation of stock-based awards and income taxes. Actual results could differ from those estimates.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Segment Information&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker, or decision making group, in deciding how to allocate resources and assess performance. The Company views its operations and manages its business as a single operating segment, which is the business of discovering and developing ADCs.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Summary of Accounting Policies&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and nine months ended September&#160;30, 2020 are consistent with those discussed in Note 2 to the consolidated financial statements in the Company&#x2019;s 2019 Annual Report on Form 10-K, except as otherwise noted below in "Recently Issued Accounting Pronouncements."&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Fair Value Measurements&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. ASC Topic&#160;820&#160;&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt;Fair Value Measurement&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;&#160;(ASC&#160;820) establishes a three-level valuation hierarchy for instruments measured at fair value. The hierarchy is based on the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Level&#160;1&#x2014;Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Level&#160;2&#x2014;Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Level&#160;3&#x2014;Inputs to the valuation methodology are unobservable and significant to the fair value measurement.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Cash and Cash Equivalents&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company considers all highly liquid investments with an original maturity, or a remaining maturity at the time of purchase, of three months or less to be cash equivalents. The Company invests excess cash primarily in money market funds, commercial paper and government agency securities, which are highly liquid and have strong credit ratings. These investments are subject to minimal credit and market risks. Cash and cash equivalents are stated at cost, which approximates market value.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Beginning&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;End&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Beginning&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;End&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Cash and cash equivalents&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;62,351&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;270,936&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;59,634&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;58,196&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Restricted cash included in other assets, noncurrent&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;371&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total cash, cash equivalents and restricted cash per statement of cash flows&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;62,672&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;271,257&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;60,005&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;58,517&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Marketable Securities&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Short-term marketable securities consist of investments in debt securities with maturities greater than three months and less than one year from the balance sheet date. The Company classifies all of its marketable securities as available-for-sale. Accordingly, these investments are recorded at fair value. Amortization and accretion of discounts and premiums are recorded as interest income within other income. Prior to the adoption of ASU 2016-13,&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt; Financial Instruments - Credit Losses&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;, unrealized gains and losses on available-for-sale securities are included in other accumulated comprehensive income (loss) as a component of stockholders&#x2019; equity until realized. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other income (expense), net, based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers various factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. Fair value is determined based on quoted market prices.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Other Assets&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company recorded other assets of $2,153 and $1,453 as of September&#160;30, 2020 and December&#160;31, 2019, respectively, comprised of $1,832 and $1,132, respectively, held by a service provider, and restricted cash of $321 at the end of each period held as security deposits for a standby letter of credit related to a facility lease. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Net Loss per Share&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without further consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury stock and if-converted methods.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;For purposes of the diluted net loss per share calculation, stock options, unvested restricted stock units (RSUs), warrants to purchase common stock and options to purchase common stock are considered to be potentially dilutive securities, but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table sets forth the outstanding potentially dilutive securities that have been excluded from the calculation of diluted net loss per share for the three and nine months ended September&#160;30, 2020 and 2019, because to include them would be anti-dilutive (in common stock equivalent shares):&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"&gt; &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:49.541%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:23.258%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.441%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:23.260%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three and Nine Months Ended&lt;br/&gt;September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three and Nine Months Ended&lt;br/&gt;September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock options&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,215,368&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,718,597&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Unvested restricted stock units&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;740,862&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;447,336&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Warrants&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;39,474&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;39,474&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,995,704&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,205,407&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Recently Issued Accounting Pronouncements&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In November 2018, the FASB issued ASU No. 2018-18, &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt;Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;. The main provisions of ASU 2018-18 include: (i) clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue when the collaborative arrangement participant is a customer in the context of a unit of account and (ii) precluding the presentation of transactions with collaborative arrangement participants that are not directly related to sales to third parties together with revenue. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The guidance per ASU 2018-18 is to be adopted retrospectively to the date of initial application of Topic 606. The Company adopted the new standard effective January 1, 2020. The adoption of this standard did not have a material impact on the Company&#x2019;s consolidated financial statements and related disclosures.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In June 2016, the FASB issued ASU 2016-13, &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt;Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;, which requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. Historically, U.S. GAAP delayed recognition of the full amount of credit losses until the loss was probable of occurring. Under this ASU, the income statement will reflect an entity&#x2019;s current estimate of all expected credit losses. The measurement of expected credit losses will be based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down of the security. This ASU is effective for annual periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The Company adopted the new standard effective January 1, 2020 using the modified retrospective method. 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style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Beginning&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;End&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Beginning&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;End&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Cash and cash equivalents&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;62,351&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;270,936&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;59,634&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;58,196&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Restricted cash included in other assets, noncurrent&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;371&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total cash, cash equivalents and restricted cash per statement of cash flows&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;62,672&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;271,257&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;60,005&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;58,517&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;</us-gaap:ScheduleOfRestrictedCashAndCashEquivalentsTextBlock>
    <us-gaap:ScheduleOfCashAndCashEquivalentsTableTextBlock
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTExNw_8fa43d94-f5d4-4f2b-bc3e-fb13dae0ae54">&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Beginning&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;End&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Beginning&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;End&lt;br/&gt;of period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Cash and cash equivalents&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;62,351&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;270,936&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;59,634&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;58,196&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Restricted cash included in other assets, noncurrent&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;371&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total cash, cash equivalents and restricted cash per statement of cash flows&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;62,672&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid 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style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:49.541%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:23.258%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.441%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:23.260%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three and Nine Months Ended&lt;br/&gt;September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three and Nine Months Ended&lt;br/&gt;September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock options&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,215,368&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,718,597&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Unvested restricted stock units&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;740,862&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;447,336&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Warrants&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;39,474&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;39,474&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,995,704&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td 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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80MC9mcmFnOjM0Y2I5ZTM2OTU0MzRhYWVhMWE2YTQ0ZmEyZjIzMDMyL3RleHRyZWdpb246MzRjYjllMzY5NTQzNGFhZWExYTZhNDRmYTJmMjMwMzJfOTEzMA_f15403c1-a369-4400-ad42-c7c044c6c8c8">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Recently Issued Accounting Pronouncements&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In November 2018, the FASB issued ASU No. 2018-18, &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt;Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;. The main provisions of ASU 2018-18 include: (i) clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue when the collaborative arrangement participant is a customer in the context of a unit of account and (ii) precluding the presentation of transactions with collaborative arrangement participants that are not directly related to sales to third parties together with revenue. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The guidance per ASU 2018-18 is to be adopted retrospectively to the date of initial application of Topic 606. The Company adopted the new standard effective January 1, 2020. The adoption of this standard did not have a material impact on the Company&#x2019;s consolidated financial statements and related disclosures.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In June 2016, the FASB issued ASU 2016-13, &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt;Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;, which requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. Historically, U.S. GAAP delayed recognition of the full amount of credit losses until the loss was probable of occurring. Under this ASU, the income statement will reflect an entity&#x2019;s current estimate of all expected credit losses. The measurement of expected credit losses will be based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down of the security. This ASU is effective for annual periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The Company adopted the new standard effective January 1, 2020 using the modified retrospective method. The adoption of this standard did not have a material impact on the Company&#x2019;s consolidated financial statements and related disclosures.&lt;/span&gt;&lt;/div&gt;</us-gaap:NewAccountingPronouncementsPolicyPolicyTextBlock>
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl80Ni9mcmFnOjk5NTdlMTUwZWRiODQxMWM5ZDkwMTI1MWE5NzI5M2NhL3RleHRyZWdpb246OTk1N2UxNTBlZGI4NDExYzlkOTAxMjUxYTk3MjkzY2FfOTMxMw_8bef03cd-e922-4e19-8c1e-8a1dbeb17394">Collaboration agreements&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Merck KGaA&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In June 2014, the Company entered into a Collaboration and Commercial License Agreement with Merck KGaA (the Merck KGaA Agreement). Upon the execution of the agreement, Merck KGaA paid the Company a nonrefundable technology access fee of $12,000 for the right to develop ADCs directed to six exclusive targets over a specified period of time. No additional fees are due when a target is designated and the commercial license to the target is granted. Merck KGaA will be responsible for the product development and marketing of any products resulting from this collaboration.&#160;All six targets were designated prior to 2018. The Company is eligible to receive milestones under the Merck KGaA Agreement. The next potential milestone payment is a development milestone of $500 on Merck KGaA&#x2019;s designation of a preclinical development candidate for a target. Revenue for the milestone is fully constrained until it is certain the milestone would be achieved.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Under the terms of the Merck KGaA Agreement, the Company and Merck KGaA develop research plans to evaluate Merck KGaA's antibodies as ADCs incorporating the Company's technology. The Company receives reimbursement for its efforts under the research plans. The goal of the research plans is to provide Merck KGaA with sufficient information to formally nominate a development candidate and begin IND-enabling studies or cease development on the designated target.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In May 2018, the Company entered into a Supply Agreement with Merck KGaA (the Merck KGaA Supply Agreement). Under the terms of the Merck KGaA Supply Agreement, the Company will provide Merck KGaA preclinical non-GMP ADC Drug Substance and clinical GMP Drug Substance for use in clinical trials associated with one of the antibodies designated under the Merck KGaA Agreement. The Company receives fees for its efforts under the Merck KGaA Supply Agreement and reimbursement equal to the supply cost. The Company may also enter into future supply agreements to provide clinical supply material should Merck KGaA pursue clinical development of any other candidates nominated under the Merck KGaA Agreement.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Accounting Analysis&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company identified the following performance obligations under the Merck KGaA agreement: (i) exclusive license and research services for six designated targets, (ii) rights to future technological improvements and (iii) participation of project team leaders and providing joint research committee services.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company is recognizing revenue related to the exclusive license and research and development services over the estimated period of the research and development services using a proportional performance model.  The Company measures proportional performance based on the costs incurred relative to the total costs expected to be incurred. To the extent that the Company receives fees for the research services as they are performed, these amounts are recorded as deferred revenue. Revenue related to future technological improvements and joint research committee services will be recognized ratably over the respective performance period (which in the case of the joint research committee services approximates the time and cost incurred each period), which are 10 and five years, respectively.&#160;The Company is continuing to reassess the estimated remaining term at each subsequent reporting period. As of December 31, 2019, the total transaction price for the Merck KGaA Agreement was $21,500, which represented the amount of consideration the Company was expected to receive for the transfer of goods and services to Merck KGaA. During the nine months ended September&#160;30, 2020, the Company decreased the fees expected to be received for research and development activities by $175 to $6,325, resulting in a revised total transaction price for the Merck KGaA Agreement of $21,325.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;During the nine months ended September&#160;30, 2020, the Company completed its performance obligations associated with one of the six designated targets. For the three months ended September&#160;30, 2020 and 2019, and the nine months ended September&#160;30, 2020 and 2019, the Company recorded collaboration revenue of $11, $800, $817, and $836, respectively, related to its efforts under the Merck KGaA Agreement. During the three and nine months ended &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;September&#160;30, 2019, the Company recognized $34 and $1,255, respectively, in collaboration revenue and corresponding research and development expense of $34 and $1,255, respectively, related to the Merck KGaA Supply Agreement.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020 and December&#160;31, 2019, the Company had $3,998 and $4,815, respectively, in deferred revenue related to the Merck KGaA Agreement and Merck KGaA Supply Agreement that will be recognized over the remaining performance period.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Takeda XMT-1522 Strategic Partnership&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In January 2016, the Company entered into a Development Collaboration and Commercial License Agreement with Takeda's wholly owned subsidiary, Millennium Pharmaceuticals, Inc. for the development and commercialization of XMT-1522 (the XMT-1522 Agreement). Under the XMT-1522 Agreement, Takeda was granted the exclusive right to commercialize XMT-1522 outside of the United States and Canada. Under the XMT-1522 Agreement, the Company was responsible for conducting certain Phase 1 development activities for XMT-1522, including the ongoing Phase 1 clinical trial, at its own expense. The parties agreed to collaborate on the further development of XMT-1522 in accordance with a global development plan (Post-Phase 1 Development). On January 2, 2019, the Company received notice from Takeda stating that Takeda was exercising its right to terminate the XMT-1522 Agreement upon 30 days&#x2019; prior written notice. The XMT-1522 Agreement terminated in accordance with its provisions, and the Company and Takeda wound down activities related to the XMT-1522 Agreement as of March 31, 2019. Under the XMT-1522 Agreement, the Company and Takeda shared equally all budgeted Post-Phase 1 Development costs through the date of termination and for a period of 30 days after the effective termination date.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;For the applicable period within the three months ended March 31, 2019, the Company was billed $200 by Takeda, representing the Company&#x2019;s share of Post-Phase 1 Development costs incurred by Takeda. This amount has been reflected as research and development costs in the consolidated statement of operations.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Takeda strategic research and development partnership&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In March 2014, the Company entered into a Research Collaboration and Commercial License Agreement with Takeda through Takeda&#x2019;s wholly owned subsidiary, Millennium Pharmaceuticals, Inc. (the 2014 Agreement). The 2014 Agreement was amended in January 2015 and amended and restated in January 2016 (the 2016 Restated Agreement). The agreements provided Takeda with the right to develop ADCs directed to a total of seven exclusive targets, designated by Takeda, over a specified period of time. On January 2, 2019, the Company received notice from Takeda stating that Takeda was exercising its right to terminate the 2016 Restated Agreement upon 45 days&#x2019; prior written notice. The 2016 Restated Agreement terminated in accordance with its provisions, and the Company and Takeda wound down activities related to the 2016 Restated Agreement as of March 31, 2019.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;During the applicable period within the three months ended March 31, 2019, the Company billed Takeda $195 related to ASC 808 costs.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Accounting Analysis&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company&#x2019;s collaboration agreements with Takeda were terminated following receipt of written notices during the first quarter of 2019. As there are no further performance obligations, the Company recognized the remaining deferred revenue of&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt; $39,965 &lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;related to the termination of the Takeda agreements in the&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt; first quarter of 2019.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Included in accounts payable as of September&#160;30, 2020 and December&#160;31, 2019 was $2,335 related to the Takeda agreements.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Summary of Contract Assets and Liabilities&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table presents changes in the balances of our contract assets and liabilities during the nine months ended September&#160;30, 2020 and 2019:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;Beginning&lt;br/&gt;of Period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Additions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Deductions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;End of Period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;Nine months ended September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract assets&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract liabilities:&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Deferred revenue&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,815&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;817&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,998&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span&gt;&lt;br/&gt;&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;Beginning&lt;br/&gt;of Period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Additions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Deductions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;End of Period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;Nine months ended September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract assets&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract liabilities:&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Deferred revenue&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;46,196&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;41,550&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,646&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New 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style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;Beginning&lt;br/&gt;of Period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Additions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Deductions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;End of Period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;Nine months ended September 30, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract assets&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract liabilities:&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Deferred revenue&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,815&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;817&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,998&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span&gt;&lt;br/&gt;&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;Beginning&lt;br/&gt;of Period&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Additions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Deductions&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Balance at&lt;br/&gt;End of Period&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;Nine months ended September 30, 2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract assets&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Contract liabilities:&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Deferred revenue&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;46,196&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;41,550&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,646&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;During the three and nine months ended September&#160;30, 2020 and 2019, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt 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0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Corporate bonds&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;12,010&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;12,010&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;U.S. Treasuries&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;13,489&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;13,489&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;37,439&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;13,489&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;23,950&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;There were no changes in valuation techniques or transfers between fair value measurement levels during the nine months ended September&#160;30, 2020 and 2019. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The carrying amounts reflected in the consolidated balance sheets for prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values due to their short-term nature.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, the carrying value of the Company&#x2019;s outstanding borrowing under the Amended Credit Facility (as defined below) approximated fair value (a Level 2 fair value measurement), reflecting interest rates currently available to the Company. The Amended Credit Facility is discussed in more detail in Note 7, &#x201c;Debt&#x201d;.&lt;/span&gt;&lt;/div&gt;</us-gaap:FairValueMeasurementInputsDisclosureTextBlock>
    <us-gaap:FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81Mi9mcmFnOjBhYTlmNmJhYWEwNzQ4YWViM2NkZWYxOTQ2OTNmMjNkL3RleHRyZWdpb246MGFhOWY2YmFhYTA3NDhhZWIzY2RlZjE5NDY5M2YyM2RfOTMx_5592dd32-831e-4153-8af9-645356e3b0ed">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table presents information about the Company's assets and liabilities regularly measured and carried at a fair value and indicates the level within fair value hierarchy of the valuation techniques utilized to determine such value as of December&#160;31, 2019. &lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company had no marketable securities as of &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;September&#160;30, 2020&lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;: &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Fair&lt;br/&gt;Value&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Quoted&#160;Prices&lt;br/&gt;in&#160;Active&lt;br/&gt;Markets&lt;br/&gt;(Level&#160;1)&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Significant&lt;br/&gt;Other&lt;br/&gt;Observable&lt;br/&gt;Inputs&lt;br/&gt;(Level&#160;2)&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Significant&lt;br/&gt;Unobservable&lt;br/&gt;Inputs&lt;br/&gt;(Level&#160;3)&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;December 31, 2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Marketable securities:&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Commercial paper&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,940&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,940&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Corporate bonds&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;12,010&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;12,010&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;U.S. Treasuries&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;13,489&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New 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Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;37,439&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81NS9mcmFnOmFlZmE3M2RhZTBlNDRiMjRhZjFlZTQyM2M5ODE5MWFkL3RleHRyZWdpb246YWVmYTczZGFlMGU0NGIyNGFmMWVlNDIzYzk4MTkxYWRfMTk4_3215e1cd-11f9-4c58-b4df-807ca05711ab">Marketable securities&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table summarizes marketable securities held at December&#160;31, 2019. &lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company had no marketable securities as of &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;September&#160;30, 2020&lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;: &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Amortized&lt;br/&gt;Cost&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Gross&lt;br/&gt;Unrealized&lt;br/&gt;Gains&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Gross&lt;br/&gt;Unrealized&lt;br/&gt;Losses&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Fair&lt;br/&gt;Value&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;December 31, 2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Commercial paper&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,940&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,940&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Corporate bonds&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,990&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;20&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;12,010&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;U.S. Treasuries&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;13,484&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;13,489&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;37,414&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;25&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;37,439&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock>
    <us-gaap:ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl81NS9mcmFnOmFlZmE3M2RhZTBlNDRiMjRhZjFlZTQyM2M5ODE5MWFkL3RleHRyZWdpb246YWVmYTczZGFlMGU0NGIyNGFmMWVlNDIzYzk4MTkxYWRfMTk5_5cce9e0f-459e-4103-a1c5-7cd2e4502696">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table summarizes marketable securities held at December&#160;31, 2019. &lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company had no marketable securities as of &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;September&#160;30, 2020&lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;: &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.127%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.741%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.602%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.744%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Amortized&lt;br/&gt;Cost&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Gross&lt;br/&gt;Unrealized&lt;br/&gt;Gains&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Gross&lt;br/&gt;Unrealized&lt;br/&gt;Losses&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Fair&lt;br/&gt;Value&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%"&gt;December 31, 2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Commercial paper&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,940&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td 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1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,037&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accrued preclinical, manufacturing and clinical expenses&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,600&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,230&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accrued professional fees and insurance&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;861&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;675&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accrued other&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;65&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;44&#160;&lt;/span&gt;&lt;/td&gt;&lt;td 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colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;8,986&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock>
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style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;September 30,&lt;br/&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;December 31,&lt;br/&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accrued payroll and related expenses&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,647&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,037&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accrued preclinical, manufacturing and clinical expenses&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" 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colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;8,986&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock>
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTQxMw_08b0afe9-19b2-4993-bd88-6236e17118ff">Debt&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;On May 8, 2019, the Company entered into a loan and security agreement (the Original Agreement) with Silicon Valley Bank (SVB) pursuant to which the Company borrowed $5,000. The Original Agreement accrued interest at a floating per annum rate equal to the greater of (i) 4.0% and (ii) 1.50% below the Prime Rate. The Original Agreement had an interest-only period through August 31, 2020.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;On August 28, 2020 (the Effective Date), the Company entered into a second amendment (the Amendment)&lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt; to its existing loan and security agreement (as amended prior to the Amendment, the Existing Credit Facility) with &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;SVB. Pursuant to the Amendment, the Company can borrow term loans in an aggregate amount of $30,000 (the Amended Credit Facility), at its option, &lt;/span&gt;&lt;span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;(i) up to $25,000 in up to five principal advances through April 30, 2022, and (ii) an additional $5,000 in one principal advance, if the Company reaches certain development milestone events, as described in the Amendment, through April 30, 2022. The Company drew $5,200 upon execution of the Amendment, the proceeds of which were used to repay the Company&#x2019;s existing balance and satisfy its obligations to SVB, including the final payment obligation under the Existing Credit Facility.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Amended Credit Facility bears interest at a floating per annum rate equal to the greater of (i) 4.25% and (ii) 1.00% above the Prime Rate, as defined. The Company is obligated to make monthly interest-only payments on each outstanding term loan commencing on the first calendar day of the month following the funding date of such term loan, and continuing on the first calendar day of each month thereafter through May 31, 2022. The interest only period may be extended through January 31, 2023 upon the achievement of a regulatory milestone, as described in the Amendment. Following the interest-only period, the Company will be required to repay the outstanding principal balance under the term loans in equal monthly payments plus interest in arrears to SVB through November 1, 2024 (the Maturity Date).&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company is also required to make a final payment to SVB equal to 5.5% of the original principal amount of the term loans then extended to the Company. This final payment is accreted under the effective interest method over the life of each term loan. The term loans are secured by substantially all of the Company's assets, except for its intellectual property which is subject to a negative pledge, and certain other customary exclusions.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;At the Company&#x2019;s option, it may prepay the outstanding principal balance of any term loans in whole but not in part, subject to a prepayment fee of: (a) 3.0% of the term loans then extended to the Company if the prepayment occurs on or prior to August 28, 2021, (b) 2.0% of the term loans then extended to the Company if the prepayment occurs after August 28, 2021 but on or prior to August 28, 2022, or (c) 1.0% of the term loans then extended to the Company if the prepayment occurs after August 28, 2022 but before November 1, 2024. The Amended Credit Facility includes customary affirmative and restrictive covenants applicable to the Company. Affirmative covenants include, among others, covenants requiring the Company to maintain its corporate existence and governmental approvals, deliver certain financial reports, maintain insurance coverage and satisfy certain requirements regarding &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;deposit accounts. The Amendment removed the requirement for the Company to maintain a minimum liquidity ratio. The restrictive covenants include, among others, requirements relating to the Company&#x2019;s ability to transfer collateral, incur additional indebtedness, engage in mergers or acquisitions, pay dividends or make other distributions, make investments, create liens, sell assets and agree to a change in control, in each case subject to certain customary exceptions.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company&#x2019;s payment obligations under the Amended Credit Facility are subject to acceleration upon the occurrence of specified events of default, which include, but are not limited to, the occurrence of a material adverse change in the Company&#x2019;s business, operations, or financial or other condition. Amounts outstanding upon the occurrence of an event of default are payable upon SVB&#x2019;s demand and shall accrue interest at an additional rate of 5.0% per annum of the past due amount outstanding. As of September&#160;30, 2020, the Company was in compliance with all covenants under the Amended Credit Facility. As such, as of September&#160;30, 2020, the classification of the loan balance as stated on the balance sheet was based on the timing of defined future payment obligations.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The unamortized issuance costs under the Existing Credit Facility were $139 as of the date of the Amendment. The Company incurred debt issuance costs paid to the lender in connection with the Amended Credit Facility of $17. The Company recorded such costs, including the settlement of the final payment obligation under the Existing Credit Facility as a discount from the carrying value of the term loans which are amortized as interest expense using the effective-interest method over the term of the Amended Credit Facility. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, there was $5,200 in term loans outstanding under the Amended Credit Facility and the debt consisted of the following:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:84.957%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;September 30,&lt;br/&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total debt&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,200&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Debt financing costs, net of accretion&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(262)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accretion related to final payment&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Long-term debt, net&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,944&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, the estimated future principal payments due are as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:84.957%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2020 (excluding the nine months ended September 30, 2020)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2021&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 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0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2023&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,080&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2024&lt;/span&gt;&lt;/td&gt;&lt;td 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      contextRef="i20a0178a16b44a089b3366764b8ff83d_D20200828-20200828"
      decimals="INF"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEwOA_dc06da9c-2070-4168-82da-37b115d55df6"
      unitRef="number">0.055</mrsn:DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal>
    <mrsn:DebtInstrumentPrepaymentFeePercentage
      contextRef="i5618dcb2bf4349d7bbc92a2fd0ef6975_D20200828-20200828"
      decimals="INF"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzExNA_bbf91713-28aa-426d-8a5f-6f1fafc59c5e"
      unitRef="number">0.030</mrsn:DebtInstrumentPrepaymentFeePercentage>
    <mrsn:DebtInstrumentPrepaymentFeePercentage
      contextRef="i1a2382de89694608bd0ddd7aaaafa1b1_D20200828-20200828"
      decimals="INF"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEyMA_89348d13-d559-4b38-ab80-2f7686538353"
      unitRef="number">0.020</mrsn:DebtInstrumentPrepaymentFeePercentage>
    <mrsn:DebtInstrumentPrepaymentFeePercentage
      contextRef="i476b73e3ee3e480ab3006d6fb3bed77e_D20200828-20200828"
      decimals="INF"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEyNg_0ecd8abf-be37-488a-a0b5-d967a8732d0c"
      unitRef="number">0.010</mrsn:DebtInstrumentPrepaymentFeePercentage>
    <mrsn:DebtInstrumentDebtDefaultAdditionalRate
      contextRef="i20a0178a16b44a089b3366764b8ff83d_D20200828-20200828"
      decimals="INF"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2NzEzMg_f29e1555-8ab6-4735-b437-2e2e2740cd31"
      unitRef="number">0.050</mrsn:DebtInstrumentDebtDefaultAdditionalRate>
    <us-gaap:DeferredFinanceCostsNet
      contextRef="i70b4d6bc15744935b8eefe34389bb283_I20200828"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTk0Mw_7f68bdc6-f437-4d41-b1af-5771464ef3de"
      unitRef="usd">139000</us-gaap:DeferredFinanceCostsNet>
    <us-gaap:DeferredFinanceCostsGross
      contextRef="iacf0da2eacac4227b0377970d5181b2a_I20200828"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzY5NjU4MTQwNTk1Mg_ff53bf36-8940-455d-b797-27ee585c3b03"
      unitRef="usd">17000</us-gaap:DeferredFinanceCostsGross>
    <us-gaap:ScheduleOfDebtTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMjE5OTAyMzI2ODg3Mw_bbab4d99-6bf3-4131-94fc-2fcfdc26549d">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, there was $5,200 in term loans outstanding under the Amended Credit Facility and the debt consisted of the following:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:84.957%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;September 30,&lt;br/&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total debt&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,200&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;td colspan="3" style="display:none"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Debt financing costs, net of accretion&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(262)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Accretion related to final payment&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Long-term debt, net&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,944&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:ScheduleOfDebtTableTextBlock>
    <us-gaap:DebtInstrumentCarryingAmount
      contextRef="i17bb20908ed64311918f13be6cfcd022_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfNzE0NjgyNTU5MzEzMg_81d68005-a8b4-4f18-b169-619cc9f8861d"
      unitRef="usd">5200000</us-gaap:DebtInstrumentCarryingAmount>
    <us-gaap:DebtInstrumentCarryingAmount
      contextRef="i2747742065f74d22a950e115eb8eb517_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfMS0xLTEtMS0w_7cc8dac7-7622-4fcd-a638-dfc94f5a60f0"
      unitRef="usd">5200000</us-gaap:DebtInstrumentCarryingAmount>
    <us-gaap:DeferredFinanceCostsNet
      contextRef="i2747742065f74d22a950e115eb8eb517_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfNC0xLTEtMS0w_bea8f5a8-8540-4df2-8bdb-01c7b9611160"
      unitRef="usd">262000</us-gaap:DeferredFinanceCostsNet>
    <us-gaap:DebtInstrumentUnamortizedPremium
      contextRef="i2747742065f74d22a950e115eb8eb517_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfNS0xLTEtMS0w_62388181-5556-45bd-af93-733e6fa43133"
      unitRef="usd">6000</us-gaap:DebtInstrumentUnamortizedPremium>
    <us-gaap:LongTermDebt
      contextRef="i2747742065f74d22a950e115eb8eb517_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RhYmxlOmZmYmRmYTY4ZDU3MDRlY2NiODFiZTY0MmU5NGJhZDZhL3RhYmxlcmFuZ2U6ZmZiZGZhNjhkNTcwNGVjY2I4MWJlNjQyZTk0YmFkNmFfNi0xLTEtMS0w_f7b27aa1-433e-414c-ab15-20b120005e34"
      unitRef="usd">4944000</us-gaap:LongTermDebt>
    <us-gaap:ScheduleOfMaturitiesOfLongTermDebtTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82NC9mcmFnOjE4ZDhmNWYzNjI2YjQ4NTU4NjcyOTczZDQ1YmQ1MzMzL3RleHRyZWdpb246MThkOGY1ZjM2MjZiNDg1NTg2NzI5NzNkNDViZDUzMzNfMTQxNA_d2365716-e9d0-4cb2-a224-c1b48f3853b5">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, the estimated future principal payments due are as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:84.957%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2020 (excluding the nine months ended September 30, 2020)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2021&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2022&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,213&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2023&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,080&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2024&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,907&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total debt&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,200&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:ScheduleOfMaturitiesOfLongTermDebtTableTextBlock>
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    <us-gaap:StockholdersEquityNoteDisclosureTextBlock
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RleHRyZWdpb246ZjI0YzM2YzRjNTc0NGQ4NmI2NWYwNTg2ZjYwMDc1ZGNfMjkxNA_fa7c8c73-22a4-4b6d-8997-c99256ecbe66">Stockholders&#x2019; equity &lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Preferred stock&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, the Company had 25,000,000 shares of authorized preferred stock. No shares of preferred stock have been issued.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;At-the-market equity offering program&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In July 2018, the Company established an at-the-market (ATM) equity offering program (the 2018 ATM) pursuant to which it offered and sold up to $75,000 of its common stock from time to time at prevailing market prices. In April 2020, the Company sold 8,938,599 and 1,962,000 shares of common stock at $5.59 per share and $7.74 per share, respectively, to raise aggregate gross proceeds of $65,153 through the 2018 ATM facility. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $62,976. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In May 2020, the Company terminated the 2018 ATM and established a new ATM equity offering program (the 2020 ATM) pursuant to which it is able to sell up to $100,000 of its common stock from time to time at prevailing market prices. As of September&#160;30, 2020, the Company had not sold any shares under the 2020 ATM.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Follow-on offering&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In June 2020, the Company sold 9,200,000 shares of common stock, in an underwritten public offering price to the public of $19.00 per share, resulting in gross proceeds of approximately $174,800. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $163,991.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Warrants&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In connection with a 2013 Series&#160;A-1 Preferred Stock issuance, the Company granted to certain investors warrants to purchase 129,491 shares of common stock. The warrants have a $0.05 per share exercise price and a contractual life of 10 years. The fair value of these warrants was recorded as a component of equity at the time of issuance. As of September&#160;30, 2020, there were warrants to purchase 39,474 shares of common stock.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Exchange warrants&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;On November 26, 2019, the Company entered into an exchange agreement with entities affiliated with Biotechnology Value Fund, L.P. (the Exchanging Stockholders), pursuant to which the Exchanging Stockholders exchanged an aggregate of 2,575,000 shares of common stock for warrants (the Exchange Warrants) to purchase an aggregate of 2,575,000 shares of common stock (subject to adjustment in the event of any stock dividends and splits, reverse stock split, merger or consolidation, change of control, reorganization or similar transaction, as described in the Exchange Warrants), with an exercise price of $0.0001 per share.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;On March 2, 2020, the Exchanging Stockholders exercised the Exchange Warrants in full on a net cashless exercise basis, resulting in the issuance of 2,574,971 shares of common stock.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Common stock&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The holders of the common stock are entitled to one vote for each share held. Common stockholders are not entitled to receive dividends, unless declared by the Board of Directors (the Board).&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;At September&#160;30, 2020 and December&#160;31, 2019, there were 6,995,704 and 7,782,582, respectively, shares of common stock reserved for the exercise of outstanding stock options, restricted stock units and warrants, as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;September 30,&lt;br/&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;December 31,&lt;br/&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock 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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfNC0zLTEtMS0w_f8113280-46c2-4a85-b36b-74f60909cb4e"
      unitRef="shares">2575000</us-gaap:CommonStockCapitalSharesReservedForFutureIssuance>
    <us-gaap:CommonStockCapitalSharesReservedForFutureIssuance
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfNS0xLTEtMS0w_d54af2f6-cda7-4c1a-9054-bce53836286e"
      unitRef="shares">6995704</us-gaap:CommonStockCapitalSharesReservedForFutureIssuance>
    <us-gaap:CommonStockCapitalSharesReservedForFutureIssuance
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl82Ny9mcmFnOmYyNGMzNmM0YzU3NDRkODZiNjVmMDU4NmY2MDA3NWRjL3RhYmxlOjA5MDczOTBhYzFmYjRkYzE4ZjU2OWE2ZDEwMmMzZGQ2L3RhYmxlcmFuZ2U6MDkwNzM5MGFjMWZiNGRjMThmNTY5YTZkMTAyYzNkZDZfNS0zLTEtMS0w_e6a70fff-c515-4c83-a089-6dae9e986196"
      unitRef="shares">7782582</us-gaap:CommonStockCapitalSharesReservedForFutureIssuance>
    <us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIxNA_b52501b6-2372-4733-b9ad-61e168753f22">Stock options&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Stock option plans&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In June 2017, the Company&#x2019;s stockholders approved the 2017 Stock Incentive Plan (the 2017 Plan). Under the 2017 Plan, up to 2,255,000 shares of common stock were initially available to be granted to the Company's employees, officers, directors, consultants and advisors in the form of options, restricted stock units (RSUs) or other stock-based awards. The number of shares of common stock issuable under the 2017 Plan will be cumulatively increased annually by 4% of the outstanding shares or such lesser amount specified by the Board. The terms of the awards are determined by the Board, subject to the provisions of the 2017 Plan. Any cancellations under the 2007 Plan, which expired in June 2017, would increase the number of shares that could be granted under the 2017 Plan. In January 2020, the number of shares of common stock issuable under the 2017 Plan was increased by 1,815,520 shares. As of September&#160;30, 2020, there were 1,320,916 shares available for future issuance under the 2017 Plan. During the nine months ended September 30, 2020, the Company granted 2,165,306 RSUs and options to purchase shares of common stock to employees under the 2017 Plan. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Inducement awards&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;On September 2, 2020, the Company granted its senior vice president of regulatory affairs an option to purchase up to 120,000 shares of common stock as an inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4). No underwriters were involved in this issuance of securities. The securities were issued pursuant to Section 4(a)(2) under the Securities Act of 1933, as amended, relating to transactions by an issuer not involving any public offering. These options are subject to terms substantially the same as the 2017 Plan.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;With respect to the stock option grants as described above, the exercise price per share will equal the fair market value of the common stock on the date of grant, and the vesting period is generally four years. Nonqualified stock options will be granted at an exercise price established by the Board at its sole discretion (which has not been less than fair market value on the date of grant) and the vesting periods may vary. Options granted as described above expire no later than 10 years from the date of grant. The Board may accelerate vesting or extend the expiration of granted options in the case of a merger, consolidation, dissolution, or liquidation of the Company.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Stock option activity&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;A summary of the options activity under the Plans is as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Number&lt;br/&gt;of&#160;Shares&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Weighted-&lt;br/&gt;Average&lt;br/&gt;Exercise&#160;Price&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Outstanding at January&#160;1, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,720,772&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5.24&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Granted&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,960,374&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;9.41&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Exercised&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(338,069)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5.13&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Cancelled&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(127,709)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;7.70&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Outstanding at September&#160;30,&#160;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,215,368&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.52&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Exercisable at September&#160;30,&#160;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,256,514&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4.87&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The weighted-average grant date fair value of options granted during the nine months ended September&#160;30, 2020 and 2019, was $6.17 and $2.47 per share, respectively.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Cash received from the exercise of stock options was $1,732 and $121 for the nine months ended September&#160;30, 2020 and 2019, respectively.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Restricted stock units (RSUs)&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;In July 2019, the Company issued RSUs with service conditions to employees. The awards cliff-vest two years after the grant date. In January 2020, the Company issued 324,932 RSUs with a service condition to employees for which the vesting term is annually over four years. Vesting of these awards is contingent on the fulfillment of the service conditions during the vesting term.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;A summary of the RSU activity under the 2017 Plan is as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:97.275%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:84.567%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:13.233%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Number of Shares&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Unvested at January&#160;1, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;447,336&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Granted&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;324,932&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Vested&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Forfeited&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(31,406)&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Unvested at September&#160;30,&#160;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;740,862&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Stock-based compensation expense&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company uses the provisions of ASC 718, &lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"&gt;Stock Compensation&lt;/span&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;, to account for all stock-based awards to employees and non-employees.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The measurement date for employee awards is generally the date of grant. Stock-based compensation expense is recognized over the requisite service period, which is generally the vesting period, using the straight-line method.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table presents stock-based compensation expense by award type included within the Company&#x2019;s condensed consolidated statement of operations and comprehensive loss:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock options&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,520&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,055&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,025&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,240&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Restricted stock units&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;335&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;184&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;962&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;184&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Employee stock purchase plan&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;63&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;46&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;196&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;186&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock-based compensation expense included in Total operating expenses&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,918&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,285&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,183&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,610&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table presents stock-based compensation expense as reflected in the Company&#x2019;s condensed consolidated statements of operations and comprehensive loss:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Research and development&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;952&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;587&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,554&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,636&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;General and administrative&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;966&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;698&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,629&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,974&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock-based compensation expense included in Total operating expenses&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,918&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,285&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,183&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,610&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As of September&#160;30, 2020, there was $15,007 and $2,269 of unrecognized stock compensation expense related to unvested stock options and unvested RSUs, respectively, that is expected to be recognized over a weighted-average period of 2.5 years and 2.6 years, respectively.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Risk-free interest rate&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;0.4&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1.9&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1.3&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2.4&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Expected dividend yield&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Expected term (years)&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.10&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.11&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.04&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5.99&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Expected stock price volatility&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;81&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;75&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;72&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;74&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"&gt;Employee Stock Purchase Plan&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;During the year ended December 31, 2017, the Board adopted, and the Company&#x2019;s stockholders approved the 2017 employee stock purchase plan (the 2017 ESPP). The Company initially reserved 225,000 shares of common stock for issuance under the 2017 ESPP. In January 2020, the number of shares of common stock for issuance under the 2017 ESPP was increased by 450,000 shares. For the nine months ended September&#160;30, 2020 and 2019, the Company issued 68,419 and 82,281, respectively, shares under the 2017 ESPP. The Company did not issue any shares under the 2017 ESPP for the three months ended September&#160;30, 2020 and 2019. As of September&#160;30, 2020, there were 656,666 shares available for issuance under the 2017 ESPP.&lt;/span&gt;&lt;/div&gt;</us-gaap:DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock>
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      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIxMg_7c0a5d6b-8bcd-4c24-b96c-4d8e86673f4d">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;A summary of the options activity under the Plans is as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Number&lt;br/&gt;of&#160;Shares&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Weighted-&lt;br/&gt;Average&lt;br/&gt;Exercise&#160;Price&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Outstanding at January&#160;1, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,720,772&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5.24&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Granted&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,960,374&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;9.41&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Exercised&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(338,069)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5.13&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Cancelled&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(127,709)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;7.70&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Outstanding at September&#160;30,&#160;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,215,368&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.52&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Exercisable at September&#160;30,&#160;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,256,514&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4.87&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock>
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIwMQ_f1ddee9e-7e74-42af-b179-ad6806ab168c">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;A summary of the RSU activity under the 2017 Plan is as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:97.275%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:84.567%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:13.233%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Number of Shares&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Unvested at January&#160;1, 2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;447,336&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Granted&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;324,932&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Vested&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Forfeited&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(31,406)&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Unvested at September&#160;30,&#160;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;740,862&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock>
    <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
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      unitRef="shares">447336</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber>
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      unitRef="shares">31406</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod>
    <us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
      contextRef="id4ba0bd274ff44048102f9d2db62142f_I20200930"
      decimals="INF"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RhYmxlOjFmMTAzNjhlYTYyYjRkMjJhY2E2YTM2ZTkwNzVhYjdiL3RhYmxlcmFuZ2U6MWYxMDM2OGVhNjJiNGQyMmFjYTZhMzZlOTA3NWFiN2JfNS0xLTEtMS0w_2c9183ff-635d-4282-b6a8-a457d9ca5eff"
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    <us-gaap:ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIwNw_62a9cbdf-e21a-40a8-8d8b-5986cb5c0b6d">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table presents stock-based compensation expense by award type included within the Company&#x2019;s condensed consolidated statement of operations and comprehensive loss:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock options&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,520&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,055&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;4,025&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,240&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Restricted stock units&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;335&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;184&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;962&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;184&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Employee stock purchase plan&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;63&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;46&#160;&lt;/span&gt;&lt;/td&gt;&lt;td 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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDIwOA_a19d4c44-2a28-4bf6-abc3-1e98ba05d300">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The following table presents stock-based compensation expense as reflected in the Company&#x2019;s condensed consolidated statements of operations and comprehensive loss:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:45.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Research and development&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;952&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;587&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,554&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,636&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;General and administrative&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;966&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;698&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,629&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,974&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Stock-based compensation expense included in Total operating expenses&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,918&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1,285&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;5,183&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;3,610&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock>
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style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.720%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:11.723%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Three Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Nine Months Ended&lt;br/&gt;September 30,&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2020&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/&gt;&lt;td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;2019&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Risk-free interest rate&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;1.3&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2.4&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Expected dividend yield&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;&#x2014;&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Expected term (years)&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.10&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6.11&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 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style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;72&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;%&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;74&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New 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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83MC9mcmFnOjNiMTk3N2Y5NGYxOTQ5NjJhNDczMzE4NGQxZGEyYjMxL3RleHRyZWdpb246M2IxOTc3Zjk0ZjE5NDk2MmE0NzMzMTg0ZDFkYTJiMzFfNDE0OQ_a7223cb3-b1bb-4d1f-b61b-4d0b61a22237"
      unitRef="shares">656666</us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant>
    <us-gaap:LesseeFinanceLeasesTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjA4Nw_dabdc741-6d05-48cf-ba21-3411ff2cecc8">Leases&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company has an operating lease for its office space in Cambridge, MA and operating and finance leases for certain equipment. In March 2020, the Company entered into the Seventh Amendment to the office space lease to extend the term of the lease through March 2026 and to provide the Company with a tenant improvement allowance of $172. The current rate per square foot that is in place through March 2021 (the original expiration date of the lease) did not change. After March 2021, there are predetermined fixed escalations of the rate as outlined in the amendment. The Company has an option to extend the lease term for an additional five years. The Company&#x2019;s exercise of this option was not considered reasonably certain as of September&#160;30, 2020. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The extension is accounted for as a lease modification. The Company assessed the lease classification of the amended office space lease at the modification date and determined that the amended office space lease should be accounted for as an operating lease. The right-of-use asset and corresponding operating lease liability have been remeasured based on the present value of remaining lease payments over the remaining extended lease term, using the incremental borrowing rate applicable as of the lease modification date. The Company determined the appropriate incremental borrowing rate by using a synthetic credit rating which was estimated based on an analysis of outstanding debt of companies with similar credit and financial profiles. Since the operating lease is a net lease, as the non-lease components (i.e., common area maintenance) are paid separately from rent based on actual costs incurred, such non-lease components were not included in the right-of-use asset and liability and are reflected as an expense in the period incurred. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As a result of the modification in March 2020, the Company recorded an increase of $9,980 to its right-of-use (ROU) asset and lease liabilities in the first quarter of 2020.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Operating leases&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Finance leases&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2020 (excluding the nine months ended September 30, 2020)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;604&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;29&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2021&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,772&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;116&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2022&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,843&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;84&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2023&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,928&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;74&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2024 and thereafter&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,904&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;18&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total lease payments&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;16,051&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value adjustment&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(4,165)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(30)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value of lease liabilities&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,886&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;291&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:LesseeFinanceLeasesTextBlock>
    <us-gaap:LesseeOperatingLeasesTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjA4Nw_e969e5c3-872f-4df9-9820-75c76828a237">Leases&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The Company has an operating lease for its office space in Cambridge, MA and operating and finance leases for certain equipment. In March 2020, the Company entered into the Seventh Amendment to the office space lease to extend the term of the lease through March 2026 and to provide the Company with a tenant improvement allowance of $172. The current rate per square foot that is in place through March 2021 (the original expiration date of the lease) did not change. After March 2021, there are predetermined fixed escalations of the rate as outlined in the amendment. The Company has an option to extend the lease term for an additional five years. The Company&#x2019;s exercise of this option was not considered reasonably certain as of September&#160;30, 2020. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;The extension is accounted for as a lease modification. The Company assessed the lease classification of the amended office space lease at the modification date and determined that the amended office space lease should be accounted for as an operating lease. The right-of-use asset and corresponding operating lease liability have been remeasured based on the present value of remaining lease payments over the remaining extended lease term, using the incremental borrowing rate applicable as of the lease modification date. The Company determined the appropriate incremental borrowing rate by using a synthetic credit rating which was estimated based on an analysis of outstanding debt of companies with similar credit and financial profiles. Since the operating lease is a net lease, as the non-lease components (i.e., common area maintenance) are paid separately from rent based on actual costs incurred, such non-lease components were not included in the right-of-use asset and liability and are reflected as an expense in the period incurred. &lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;As a result of the modification in March 2020, the Company recorded an increase of $9,980 to its right-of-use (ROU) asset and lease liabilities in the first quarter of 2020.&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Operating leases&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Finance leases&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2020 (excluding the nine months ended September 30, 2020)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;604&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;29&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2021&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,772&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;116&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2022&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,843&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;84&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2023&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,928&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;74&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2024 and thereafter&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,904&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;18&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total lease payments&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;16,051&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value adjustment&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(4,165)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(30)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value of lease liabilities&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,886&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;291&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:LesseeOperatingLeasesTextBlock>
    <mrsn:TenantImprovementAllowance
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      unitRef="usd">172000</mrsn:TenantImprovementAllowance>
    <us-gaap:LesseeOperatingLeaseRenewalTerm
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    <mrsn:LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability
      contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMTg3Ng_17bf2ad7-0e0d-43c4-92e6-a47d8c390cf8"
      unitRef="usd">9980000</mrsn:LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability>
    <mrsn:LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets
      contextRef="ia39fc6d936b3453e9961aed2896c6015_D20200101-20200331"
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      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMTg3Ng_bd987a7e-2949-49b0-bab4-6f34c352584d"
      unitRef="usd">9980000</mrsn:LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets>
    <us-gaap:FinanceLeaseLiabilityMaturityTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjE5OTAyMzI1NzY0Ng_0706a074-5ea1-4f27-8d39-6f53ebc1109e">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Operating leases&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Finance leases&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2020 (excluding the nine months ended September 30, 2020)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;604&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;29&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2021&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,772&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;116&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2022&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,843&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;84&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2023&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,928&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;74&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2024 and thereafter&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,904&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;18&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total lease payments&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;16,051&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value adjustment&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(4,165)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(30)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value of lease liabilities&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,886&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;291&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:FinanceLeaseLiabilityMaturityTableTextBlock>
    <us-gaap:LesseeOperatingLeaseLiabilityMaturityTableTextBlock
      contextRef="i002d75d383a541e289ed40d9e33f45b2_D20200101-20200930"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RleHRyZWdpb246NWE2OTQyYzFjN2ZmNGE1ZWJjNzljNThkZTM0YTE3MGNfMjE5OTAyMzI1NzY0Ng_64854a8f-d1fe-4981-8ee9-a0c68003bb38">&lt;div style="margin-bottom:12pt"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"&gt;Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:&lt;/span&gt;&lt;/div&gt;&lt;div style="margin-bottom:12pt"&gt;&lt;table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"&gt;&lt;tr&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:70.214%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.842%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:0.601%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;td style="width:1.0%"/&gt;&lt;td style="width:12.843%"/&gt;&lt;td style="width:0.1%"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Operating leases&lt;/span&gt;&lt;/td&gt;&lt;td colspan="3" style="padding:0 1pt"/&gt;&lt;td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%"&gt;Finance leases&lt;/span&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2020 (excluding the nine months ended September 30, 2020)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;604&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;29&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2021&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,772&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;116&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2022&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,843&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;84&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2023&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2,928&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;74&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;2024 and thereafter&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;6,904&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;18&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Total lease payments&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;16,051&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;321&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value adjustment&lt;/span&gt;&lt;/td&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(4,165)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#cceeff;padding:0 1pt"/&gt;&lt;td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;(30)&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;Present value of lease liabilities&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;11,886&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;td colspan="3" style="background-color:#ffffff;padding:0 1pt"/&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;$&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"&gt;&lt;span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"&gt;291&#160;&lt;/span&gt;&lt;/td&gt;&lt;td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</us-gaap:LesseeOperatingLeaseLiabilityMaturityTableTextBlock>
    <us-gaap:LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
      contextRef="i2747742065f74d22a950e115eb8eb517_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMS0xLTEtMS0w_1ee253ab-d130-4f87-b93f-fb5743df7556"
      unitRef="usd">604000</us-gaap:LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear>
    <us-gaap:FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear
      contextRef="i2747742065f74d22a950e115eb8eb517_I20200930"
      decimals="-3"
      id="id3VybDovL2RvY3MudjEvZG9jOjZjZTNiN2UwYzBlYjRlN2Y4OTNkZDFkYTEyYTJkYjZmL3NlYzo2Y2UzYjdlMGMwZWI0ZTdmODkzZGQxZGExMmEyZGI2Zl83My9mcmFnOjVhNjk0MmMxYzdmZjRhNWViYzc5YzU4ZGUzNGExNzBjL3RhYmxlOjk3ZTA3NjFiYTYzNDQ2OWNiMjM5N2Q5N2FjNTVmZDIzL3RhYmxlcmFuZ2U6OTdlMDc2MWJhNjM0NDY5Y2IyMzk3ZDk3YWM1NWZkMjNfMS0zLTEtMS0w_0b6891c8-83e7-4b5c-aaac-e37a27985f6c"
      unitRef="usd">29000</us-gaap:FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear>
    <us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217996295080">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Cover Page - shares<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Nov. 04, 2020</div></th>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_CoverAbstract', window );"><strong>Cover [Abstract]</strong></a></td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_DocumentPeriodEndDate', window );">Document Period End Date</a></td>
<td class="text">Sep. 30,  2020<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityFileNumber', window );">Entity File Number</a></td>
<td class="text">001-38129<span></span>
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<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityRegistrantName', window );">Entity Registrant Name</a></td>
<td class="text">Mersana Therapeutics,&#160;Inc.<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityIncorporationStateCountryCode', window );">Entity Incorporation, State or Country Code</a></td>
<td class="text">DE<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityTaxIdentificationNumber', window );">Entity Tax Identification Number</a></td>
<td class="text">04-3562403<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityAddressAddressLine1', window );">Entity Address, Address Line One</a></td>
<td class="text">840 Memorial Drive<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityAddressCityOrTown', window );">Entity Address, City or Town</a></td>
<td class="text">Cambridge<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityAddressStateOrProvince', window );">Entity Address, State or Province</a></td>
<td class="text">MA<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityAddressPostalZipCode', window );">Entity Address, Postal Zip Code</a></td>
<td class="text">02139<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_CityAreaCode', window );">City Area Code</a></td>
<td class="text">617<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_LocalPhoneNumber', window );">Local Phone Number</a></td>
<td class="text">498-0020<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_Security12bTitle', window );">Title of 12(b) Security</a></td>
<td class="text">Common Stock, $0.0001 par value<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_TradingSymbol', window );">Trading Symbol</a></td>
<td class="text">MRSN<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_SecurityExchangeName', window );">Security Exchange Name</a></td>
<td class="text">NASDAQ<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityCurrentReportingStatus', window );">Entity Current Reporting Status</a></td>
<td class="text">Yes<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityInteractiveDataCurrent', window );">Entity Interactive Data Current</a></td>
<td class="text">Yes<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityFilerCategory', window );">Entity Filer Category</a></td>
<td class="text">Accelerated Filer<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntitySmallBusiness', window );">Entity Small Business</a></td>
<td class="text">true<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityEmergingGrowthCompany', window );">Entity Emerging Growth Company</a></td>
<td class="text">true<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityExTransitionPeriod', window );">Entity Ex Transition Period</a></td>
<td class="text">true<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityShellCompany', window );">Entity Shell Company</a></td>
<td class="text">false<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityCommonStockSharesOutstanding', window );">Entity Common Stock, Shares Outstanding</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">68,497,425<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_EntityCentralIndexKey', window );">Entity Central Index Key</a></td>
<td class="text">0001442836<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_CurrentFiscalYearEndDate', window );">Current Fiscal Year End Date</a></td>
<td class="text">--12-31<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_DocumentFiscalYearFocus', window );">Document Fiscal Year Focus</a></td>
<td class="text">2020<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_DocumentFiscalPeriodFocus', window );">Document Fiscal Period Focus</a></td>
<td class="text">Q3<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_dei_AmendmentFlag', window );">Amendment Flag</a></td>
<td class="text">false<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
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<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_AmendmentFlag">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_AmendmentFlag</td>
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<td>dei_</td>
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<td>xbrli:booleanItemType</td>
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<td><strong> Balance Type:</strong></td>
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</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_CityAreaCode">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Area code of city</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_CityAreaCode</td>
</tr>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
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<td><strong> Balance Type:</strong></td>
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<td>duration</td>
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</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_CoverAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Cover page.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_CoverAbstract</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_CurrentFiscalYearEndDate">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>End date of current fiscal year in the format --MM-DD.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_CurrentFiscalYearEndDate</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentFiscalPeriodFocus">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Fiscal period values are FY, Q1, Q2, and Q3.  1st, 2nd and 3rd quarter 10-Q or 10-QT statements have value Q1, Q2, and Q3 respectively, with 10-K, 10-KT or other fiscal year statements having FY.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentFiscalPeriodFocus</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>This is focus fiscal year of the document report in YYYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentFiscalYearFocus</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentPeriodEndDate">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented.  If there is no historical data in the report, use the filing date. The format of the date is YYYY-MM-DD.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentPeriodEndDate</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentQuarterlyReport">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true only for a form used as an quarterly report.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Form 10-Q<br> -Number 240<br> -Section 308<br> -Subsection a<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentQuarterlyReport</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
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<td><strong> Data Type:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentTransitionReport">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true only for a form used as a transition report.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Forms 10-K, 10-Q, 20-F<br> -Number 240<br> -Section 13<br> -Subsection a-1<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentTransitionReport</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentType">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentType</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>dei:submissionTypeItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressAddressLine1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Address Line 1 such as Attn, Building Name, Street Name</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressAddressLine1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressCityOrTown">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Name of the City or Town</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressCityOrTown</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressPostalZipCode">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Code for the postal or zip code</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressPostalZipCode</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressStateOrProvince">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Name of the state or province.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressStateOrProvince</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:stateOrProvinceItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityCentralIndexKey">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityCentralIndexKey</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:centralIndexKeyItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityCommonStockSharesOutstanding">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityCommonStockSharesOutstanding</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityCurrentReportingStatus">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicate 'Yes' or 'No' whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityCurrentReportingStatus</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:yesNoItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityEmergingGrowthCompany">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicate if registrant meets the emerging growth company criteria.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityEmergingGrowthCompany</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityExTransitionPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicate if an emerging growth company has elected not to use the extended transition period for complying with any new or revised financial accounting standards.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Securities Act<br> -Number 7A<br> -Section B<br> -Subsection 2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityExTransitionPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityFileNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityFileNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:fileNumberItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityFilerCategory">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicate whether the registrant is one of the following: Large Accelerated Filer, Accelerated Filer, Non-accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityFilerCategory</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:filerCategoryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityIncorporationStateCountryCode">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Two-character EDGAR code representing the state or country of incorporation.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityIncorporationStateCountryCode</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:edgarStateCountryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityInteractiveDataCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation S-T<br> -Number 232<br> -Section 405<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityInteractiveDataCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:yesNoItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityRegistrantName">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityRegistrantName</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityShellCompany">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the registrant is a shell company as defined in Rule 12b-2 of the Exchange Act.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityShellCompany</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntitySmallBusiness">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicates that the company is a Smaller Reporting Company (SRC).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntitySmallBusiness</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityTaxIdentificationNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Regulation 12B<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityTaxIdentificationNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:employerIdItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_LocalPhoneNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Local phone number for entity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_LocalPhoneNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_Security12bTitle">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Title of a 12(b) registered security.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection b<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_Security12bTitle</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:securityTitleItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_SecurityExchangeName">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Name of the Exchange on which a security is registered.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection d1-1<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_SecurityExchangeName</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:edgarExchangeCodeItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_TradingSymbol">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Trading symbol of an instrument as listed on an exchange.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_TradingSymbol</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:tradingSymbolItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>12
<FILENAME>R2.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983424200">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Condensed Consolidated Balance Sheets - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AssetsCurrentAbstract', window );"><strong>Current assets:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashAndCashEquivalentsAtCarryingValue', window );">Cash and cash equivalents</a></td>
<td class="nump">$ 270,936<span></span>
</td>
<td class="nump">$ 62,351<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent', window );">Short-term marketable securities</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">37,439<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PrepaidExpenseAndOtherAssetsCurrent', window );">Prepaid expenses and other current assets</a></td>
<td class="nump">3,998<span></span>
</td>
<td class="nump">1,536<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AssetsCurrent', window );">Total current assets</a></td>
<td class="nump">274,934<span></span>
</td>
<td class="nump">101,326<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PropertyPlantAndEquipmentNet', window );">Property and equipment, net</a></td>
<td class="nump">1,698<span></span>
</td>
<td class="nump">2,164<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingLeaseRightOfUseAsset', window );">Operating lease right-of-use assets</a></td>
<td class="nump">11,343<span></span>
</td>
<td class="nump">2,598<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherAssetsNoncurrent', window );">Other assets</a></td>
<td class="nump">2,153<span></span>
</td>
<td class="nump">1,453<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_Assets', window );">Total assets</a></td>
<td class="nump">290,128<span></span>
</td>
<td class="nump">107,541<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LiabilitiesCurrentAbstract', window );"><strong>Current liabilities:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccountsPayableCurrent', window );">Accounts payable</a></td>
<td class="nump">4,528<span></span>
</td>
<td class="nump">7,296<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccruedLiabilitiesCurrent', window );">Accrued expenses</a></td>
<td class="nump">11,173<span></span>
</td>
<td class="nump">8,986<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiabilityCurrent', window );">Deferred revenue</a></td>
<td class="nump">3,998<span></span>
</td>
<td class="nump">4,815<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingLeaseLiabilityCurrent', window );">Operating lease liabilities</a></td>
<td class="nump">1,280<span></span>
</td>
<td class="nump">2,219<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtCurrent', window );">Short-term debt</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">667<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherLiabilitiesCurrent', window );">Other liabilities</a></td>
<td class="nump">91<span></span>
</td>
<td class="nump">87<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LiabilitiesCurrent', window );">Total current liabilities</a></td>
<td class="nump">21,070<span></span>
</td>
<td class="nump">24,070<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingLeaseLiabilityNoncurrent', window );">Operating lease liabilities</a></td>
<td class="nump">10,606<span></span>
</td>
<td class="nump">677<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtNoncurrent', window );">Long-term debt, net</a></td>
<td class="nump">4,944<span></span>
</td>
<td class="nump">4,201<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherLiabilitiesNoncurrent', window );">Other liabilities</a></td>
<td class="nump">200<span></span>
</td>
<td class="nump">275<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_Liabilities', window );">Total liabilities</a></td>
<td class="nump">36,820<span></span>
</td>
<td class="nump">29,223<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommitmentsAndContingencies', window );">Commitments (Note&#160;11)</a></td>
<td class="text"> <span></span>
</td>
<td class="text"> <span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquityAbstract', window );"><strong>Stockholders' equity:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PreferredStockValue', window );">Preferred stock, $0.0001 par value; 25,000,000 shares authorized; 0 shares issued and outstanding at September&#160;30, 2020 and December&#160;31, 2019, respectively</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockValue', window );">Common stock,$0.0001 par value; 175,000,000 shares authorized; 68,470,081 and 45,388,023&#160;shares issued and outstanding at September&#160;30, 2020 and December&#160;31, 2019, respectively</a></td>
<td class="nump">7<span></span>
</td>
<td class="nump">5<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdditionalPaidInCapitalCommonStock', window );">Additional paid-in capital</a></td>
<td class="nump">504,876<span></span>
</td>
<td class="nump">270,662<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax', window );">Accumulated other comprehensive income (loss)</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">25<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RetainedEarningsAccumulatedDeficit', window );">Accumulated deficit</a></td>
<td class="num">(251,575)<span></span>
</td>
<td class="num">(192,374)<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Total stockholders&#8217; equity</a></td>
<td class="nump">253,308<span></span>
</td>
<td class="nump">78,318<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LiabilitiesAndStockholdersEquity', window );">Total liabilities and stockholders&#8217; equity</a></td>
<td class="nump">$ 290,128<span></span>
</td>
<td class="nump">$ 107,541<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccountsPayableCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.19(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccountsPayableCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccruedLiabilitiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.20)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccruedLiabilitiesCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr>
<td><strong> Data Type:</strong></td>
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</tr>
<tr>
<td><strong> Balance Type:</strong></td>
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</tr>
<tr>
<td><strong> Period Type:</strong></td>
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</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(30)(a)(4))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 11<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=d3e637-108580<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(23)(a)(3))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14A<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669686-108580<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 40<br> -Section 65<br> -Paragraph 2<br> -Subparagraph (h)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121370832&amp;loc=SL117420844-207641<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 40<br> -Section 65<br> -Paragraph 2<br> -Subparagraph (g)(2)(ii)<br> -URI http://asc.fasb.org/extlink&amp;oid=121370832&amp;loc=SL117420844-207641<br><br>Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=d3e681-108580<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AdditionalPaidInCapitalCommonStock">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Value received from shareholders in common stock-related transactions that are in excess of par value or stated value and amounts received from other stock-related transactions. Includes only common stock transactions (excludes preferred stock transactions). May be called contributed capital, capital in excess of par, capital surplus, or paid-in capital.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(30)(a)(1))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AdditionalPaidInCapitalCommonStock</td>
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<td><strong> Data Type:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_Assets">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(11))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (bb)<br> -URI http://asc.fasb.org/extlink&amp;oid=121559654&amp;loc=d3e5710-111685<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 25<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=116870748&amp;loc=SL6758485-165988<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (d)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(12))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br><br>Reference 10: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_Assets</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AssetsCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6801-107765<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 25<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=116870748&amp;loc=SL6758485-165988<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (bb)<br> -URI http://asc.fasb.org/extlink&amp;oid=121559654&amp;loc=d3e5710-111685<br><br>Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.9)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6676-107765<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AssetsCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AssetsCurrentAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AssetsCurrentAbstract</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 326<br> -SubTopic 30<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121558606&amp;loc=SL82898722-210454<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 45<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=121553693&amp;loc=d3e26626-111562<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CashAndCashEquivalentsAtCarryingValue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 4<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3044-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6676-107765<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CashAndCashEquivalentsAtCarryingValue</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.25)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03.(a),19)<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03.17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 450<br> -SubTopic 20<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121557415&amp;loc=d3e14326-108349<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommitmentsAndContingencies</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr>
<td><strong> Data Type:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
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</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CommonStockValue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockValue</td>
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<td><strong> Balance Type:</strong></td>
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<tr>
<td><strong> Period Type:</strong></td>
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</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ContractWithCustomerLiabilityCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130531-203044<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130532-203044<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerLiabilityCurrent</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
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</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_Liabilities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 25<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=116870748&amp;loc=SL6758485-165988<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (bb)<br> -URI http://asc.fasb.org/extlink&amp;oid=121559654&amp;loc=d3e5710-111685<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.19-26)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121559654&amp;loc=d3e5710-111685<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br><br>Reference 7: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (d)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_Liabilities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
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</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LiabilitiesAndStockholdersEquity">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(23))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(25))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(32))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LiabilitiesAndStockholdersEquity</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
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</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LiabilitiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (bb)<br> -URI http://asc.fasb.org/extlink&amp;oid=121559654&amp;loc=d3e5710-111685<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 25<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=116870748&amp;loc=SL6758485-165988<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.21)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121559654&amp;loc=d3e5710-111685<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LiabilitiesCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LiabilitiesCurrentAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LiabilitiesCurrentAbstract</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
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</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LongTermDebtCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.19,20)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtCurrent</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
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</tr>
<tr>
<td><strong> Period Type:</strong></td>
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</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LongTermDebtNoncurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.22)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtNoncurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OperatingLeaseLiabilityCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Present value of lessee's discounted obligation for lease payments from operating lease, classified as current.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121603541&amp;loc=SL77918627-209977<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingLeaseLiabilityCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OperatingLeaseLiabilityNoncurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121603541&amp;loc=SL77918627-209977<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingLeaseLiabilityNoncurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OperatingLeaseRightOfUseAsset">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's right to use underlying asset under operating lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121603541&amp;loc=SL77918627-209977<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingLeaseRightOfUseAsset</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherAssetsNoncurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of noncurrent assets classified as other.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherAssetsNoncurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherLiabilitiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of liabilities classified as other, due within one year or the normal operating cycle, if longer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6904-107765<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6911-107765<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.20)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherLiabilitiesCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherLiabilitiesNoncurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.24)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherLiabilitiesNoncurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PreferredStockValue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PreferredStockValue</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PrepaidExpenseAndOtherAssetsCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(7))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6676-107765<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(8))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PrepaidExpenseAndOtherAssetsCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PropertyPlantAndEquipmentNet">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(14))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 360<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6391035&amp;loc=d3e2868-110229<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(8))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(13))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PropertyPlantAndEquipmentNet</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RetainedEarningsAccumulatedDeficit">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The cumulative amount of the reporting entity's undistributed earnings or deficit.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(30)(a)(3))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 65<br> -Paragraph 15<br> -Subparagraph (g)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121322162&amp;loc=SL121327923-165333<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(23)(a)(4))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 40<br> -Section 65<br> -Paragraph 2<br> -Subparagraph (h)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121370832&amp;loc=SL117420844-207641<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 40<br> -Section 65<br> -Paragraph 2<br> -Subparagraph (g)(2)(i)<br> -URI http://asc.fasb.org/extlink&amp;oid=121370832&amp;loc=SL117420844-207641<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RetainedEarningsAccumulatedDeficit</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 310<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SAB Topic 4.E)<br> -URI http://asc.fasb.org/extlink&amp;oid=27010918&amp;loc=d3e74512-122707<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(31))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(30))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br><br>Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217998991560">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares<br></strong></div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquityAbstract', window );"><strong>Stockholders' equity:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PreferredStockParOrStatedValuePerShare', window );">Preferred stock, par value (in dollars per share)</a></td>
<td class="nump">$ 0.0001<span></span>
</td>
<td class="nump">$ 0.0001<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PreferredStockSharesAuthorized', window );">Preferred stock, shares authorized (in shares)</a></td>
<td class="nump">25,000,000<span></span>
</td>
<td class="nump">25,000,000<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PreferredStockSharesIssued', window );">Preferred stock, shares issued (in shares)</a></td>
<td class="nump">0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PreferredStockSharesOutstanding', window );">Preferred stock, shares outstanding (in shares)</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockParOrStatedValuePerShare', window );">Common stock, par value (in dollars per share)</a></td>
<td class="nump">$ 0.0001<span></span>
</td>
<td class="nump">$ 0.0001<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockSharesAuthorized', window );">Common stock, shares authorized (in shares)</a></td>
<td class="nump">175,000,000<span></span>
</td>
<td class="nump">175,000,000<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockSharesIssued', window );">Common stock, shares issued (in shares)</a></td>
<td class="nump">68,470,081<span></span>
</td>
<td class="nump">45,388,023<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockSharesOutstanding', window );">Common stock, shares outstanding (in shares)</a></td>
<td class="nump">68,470,081<span></span>
</td>
<td class="nump">45,388,023<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CommonStockParOrStatedValuePerShare">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Face amount or stated value per share of common stock.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockParOrStatedValuePerShare</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The maximum number of common shares permitted to be issued by an entity's charter and bylaws.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockSharesAuthorized</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockSharesIssued</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockSharesOutstanding</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PreferredStockParOrStatedValuePerShare</td>
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<tr>
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<td>na</td>
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<tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PreferredStockSharesAuthorized</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PreferredStockSharesIssued</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PreferredStockSharesOutstanding">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PreferredStockSharesOutstanding</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StockholdersEquityAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StockholdersEquityAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986635144">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncomeStatementAbstract', window );"><strong>Income Statement [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="nump">$ 11<span></span>
</td>
<td class="nump">$ 844<span></span>
</td>
<td class="nump">$ 817<span></span>
</td>
<td class="nump">$ 42,081<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingExpensesAbstract', window );"><strong>Operating expenses:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ResearchAndDevelopmentExpense', window );">Research and development</a></td>
<td class="nump">16,546<span></span>
</td>
<td class="nump">13,701<span></span>
</td>
<td class="nump">44,179<span></span>
</td>
<td class="nump">42,610<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_GeneralAndAdministrativeExpense', window );">General and administrative</a></td>
<td class="nump">5,881<span></span>
</td>
<td class="nump">4,436<span></span>
</td>
<td class="nump">15,988<span></span>
</td>
<td class="nump">13,072<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingExpenses', window );">Total operating expenses</a></td>
<td class="nump">22,427<span></span>
</td>
<td class="nump">18,137<span></span>
</td>
<td class="nump">60,167<span></span>
</td>
<td class="nump">55,682<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NonoperatingIncomeExpenseAbstract', window );"><strong>Other income (expense):</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_InvestmentIncomeInterest', window );">Interest income</a></td>
<td class="nump">19<span></span>
</td>
<td class="nump">608<span></span>
</td>
<td class="nump">414<span></span>
</td>
<td class="nump">1,785<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_InterestExpense', window );">Interest expense</a></td>
<td class="num">(92)<span></span>
</td>
<td class="num">(107)<span></span>
</td>
<td class="num">(267)<span></span>
</td>
<td class="num">(146)<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NonoperatingIncomeExpense', window );">Total other income (expense), net</a></td>
<td class="num">(73)<span></span>
</td>
<td class="nump">501<span></span>
</td>
<td class="nump">147<span></span>
</td>
<td class="nump">1,639<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net loss</a></td>
<td class="num">(22,489)<span></span>
</td>
<td class="num">(16,792)<span></span>
</td>
<td class="num">(59,203)<span></span>
</td>
<td class="num">(11,962)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract', window );"><strong>Other comprehensive loss</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent', window );">Unrealized gain (loss) on marketable securities</a></td>
<td class="num">(2)<span></span>
</td>
<td class="nump">17<span></span>
</td>
<td class="num">(25)<span></span>
</td>
<td class="nump">36<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ComprehensiveIncomeNetOfTax', window );">Comprehensive loss</a></td>
<td class="num">(22,491)<span></span>
</td>
<td class="num">(16,775)<span></span>
</td>
<td class="num">(59,228)<span></span>
</td>
<td class="num">(11,926)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted', window );">Net income (loss) attributable to common stockholders - diluted</a></td>
<td class="num">(22,489)<span></span>
</td>
<td class="num">(16,792)<span></span>
</td>
<td class="num">(59,203)<span></span>
</td>
<td class="num">(11,962)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic', window );">Net income (loss) attributable to common stockholders - basic</a></td>
<td class="num">$ (22,489)<span></span>
</td>
<td class="num">$ (16,792)<span></span>
</td>
<td class="num">$ (59,203)<span></span>
</td>
<td class="num">$ (11,962)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EarningsPerShareBasicAndDiluted', window );">Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)</a></td>
<td class="num">$ (0.33)<span></span>
</td>
<td class="num">$ (0.35)<span></span>
</td>
<td class="num">$ (1.00)<span></span>
</td>
<td class="num">$ (0.28)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic', window );">Weighted-average number of shares of common stock used in net income (loss) per share attributable to common stockholders - basic (in shares)</a></td>
<td class="nump">68,419,192<span></span>
</td>
<td class="nump">47,833,607<span></span>
</td>
<td class="nump">59,086,202<span></span>
</td>
<td class="nump">42,011,340<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding', window );">Weighted-average number of shares of common stock used in net income (loss) per share attributable to common stockholders - diluted (in shares)</a></td>
<td class="nump">68,419,192<span></span>
</td>
<td class="nump">47,833,607<span></span>
</td>
<td class="nump">59,086,202<span></span>
</td>
<td class="nump">42,011,340<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ComprehensiveIncomeNetOfTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 220<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-04(22))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400993&amp;loc=SL114874131-224263<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SX 210.5-03(24))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=d3e557-108580<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 220<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-04(26))<br> -URI http://asc.fasb.org/extlink&amp;oid=120399700&amp;loc=SL114874048-224260<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1B<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669625-108580<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1A<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669619-108580<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ComprehensiveIncomeNetOfTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_EarningsPerShareBasicAndDiluted">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements.  Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period.  Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 7<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=d3e1337-109256<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_EarningsPerShareBasicAndDiluted</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_GeneralAndAdministrativeExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SX 210.5-03.4)<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_GeneralAndAdministrativeExpense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncomeStatementAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncomeStatementAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_InterestExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of the cost of borrowed funds accounted for as interest expense.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 20<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=6450988&amp;loc=d3e26243-108391<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 30<br> -Section 45<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=119993939&amp;loc=d3e28555-108399<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (d)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (210.5-03(11))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 220<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-04.9)<br> -URI http://asc.fasb.org/extlink&amp;oid=120399700&amp;loc=SL114874048-224260<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_InterestExpense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_InvestmentIncomeInterest">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SX 210.5-03.7(b))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_InvestmentIncomeInterest</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetIncomeLoss">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1A<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669619-108580<br><br>Reference 2: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 31<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8924-108599<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 11<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22694-107794<br><br>Reference 4: 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-SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 18: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22583-107794<br><br>Reference 19: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 20: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 60B<br> -Subparagraph (a)<br> -URI 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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetIncomeLoss</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 4<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22595-107794<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 10<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=d3e1448-109256<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 11<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22694-107794<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 11<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=d3e1377-109256<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=6371337&amp;loc=d3e3550-109257<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 11<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22694-107794<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 60B<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=SL5780133-109256<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 10: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 31<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8924-108599<br><br>Reference 11: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 12: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22583-107794<br><br>Reference 13: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 60B<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=SL5780133-109256<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=6371337&amp;loc=d3e3550-109257<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 16<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=d3e1505-109256<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NonoperatingIncomeExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SX 210.5-03.7)<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingExpenses</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingExpensesAbstract</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1A<br> -Subparagraph (c)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=109239629&amp;loc=SL4573702-111684<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 19<br> -URI http://asc.fasb.org/extlink&amp;oid=108774443&amp;loc=SL4569616-111683<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 20<br> -URI http://asc.fasb.org/extlink&amp;oid=108774443&amp;loc=SL4569643-111683<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 985<br> -SubTopic 20<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6501960&amp;loc=d3e128462-111756<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 730<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6420194&amp;loc=d3e21568-108373<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ResearchAndDevelopmentExpense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
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</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 40<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9031-108599<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 41<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9038-108599<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130543-203045<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 42<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9054-108599<br><br>Reference 10: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130545-203045<br><br>Reference 11: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 924<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 11.L)<br> -URI http://asc.fasb.org/extlink&amp;oid=6472922&amp;loc=d3e499488-122856<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=6371337&amp;loc=d3e3550-109257<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 16<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=d3e1505-109256<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=6371337&amp;loc=d3e3550-109257<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 10<br> -URI http://asc.fasb.org/extlink&amp;oid=121326447&amp;loc=d3e1448-109256<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_WeightedAverageNumberOfSharesOutstandingBasic</td>
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<td>na</td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217905486120">
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<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Condensed Consolidated Statements of Stockholders' Equity - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th"><div>Total</div></th>
<th class="th"><div>ATM</div></th>
<th class="th"><div>Public Stock Offering</div></th>
<th class="th"><div>Common&#160;Stock</div></th>
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<div>ATM</div>
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<div>Additional Paid-in Capital </div>
<div>Public Stock Offering</div>
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<th class="th"><div>Accumulated Other Comprehensive Income (Loss)</div></th>
<th class="th"><div>Accumulated Deficit</div></th>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at beginning of period (in shares) at Dec. 31, 2018</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">23,234,472<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at beginning of period at Dec. 31, 2018</a></td>
<td class="nump">$ 8,795<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 3<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 172,966<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">$ (8)<span></span>
</td>
<td class="num">$ (164,166)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercise of stock options (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">12,192<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised', window );">Exercise of stock options</a></td>
<td class="nump">42<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">42<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Issuance of common stock under public offering, net of issuance costs (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">24,437,500<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueNewIssues', window );">Issuance of common stock under public offering, net of issuance costs</a></td>
<td class="nump">92,162<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 2<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">92,160<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">1,164<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,164<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="nump">8<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">8<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="nump">21,901<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">21,901<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Mar. 31, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">47,684,164<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Mar. 31, 2019</a></td>
<td class="nump">124,072<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">266,332<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(142,265)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at beginning of period (in shares) at Dec. 31, 2018</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">23,234,472<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at beginning of period at Dec. 31, 2018</a></td>
<td class="nump">8,795<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 3<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">172,966<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(8)<span></span>
</td>
<td class="num">(164,166)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(11,962)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Sep. 30, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">47,882,897<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Sep. 30, 2019</a></td>
<td class="nump">93,045<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">269,140<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">28<span></span>
</td>
<td class="num">(176,128)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at beginning of period (in shares) at Mar. 31, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">47,684,164<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at beginning of period at Mar. 31, 2019</a></td>
<td class="nump">124,072<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">266,332<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(142,265)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercise of stock options (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">32,693<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised', window );">Exercise of stock options</a></td>
<td class="nump">58<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">58<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans', window );">Purchase of common stock under ESPP (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">82,281<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition', window );">Purchase of common stock under ESPP</a></td>
<td class="nump">283<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">283<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">1,161<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,161<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="nump">11<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">11<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(17,071)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(17,071)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Jun. 30, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">47,799,138<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Jun. 30, 2019</a></td>
<td class="nump">108,514<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">267,834<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">11<span></span>
</td>
<td class="num">(159,336)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised', window );">Exercise of stock options and warrants (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">83,759<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised', window );">Exercise of stock options and warrants</a></td>
<td class="nump">21<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">21<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">1,285<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,285<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="nump">17<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">17<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(16,792)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(16,792)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Sep. 30, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">47,882,897<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Sep. 30, 2019</a></td>
<td class="nump">93,045<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">269,140<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">28<span></span>
</td>
<td class="num">(176,128)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares', window );">Retirement of common stock in exchange for common stock warrant (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(2,575,000)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantValue', window );">Retirement of common stock in exchange for common stock warrant</a></td>
<td class="num">(8,986)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(8,986)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued', window );">Issuance of common stock warrant in exchange for retirement of common stock</a></td>
<td class="nump">8,986<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">8,986<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans', window );">Purchase of common stock under ESPP (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">57,792<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition', window );">Purchase of common stock under ESPP</a></td>
<td class="nump">206<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">206<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised', window );">Exercise of stock options and warrants (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">22,334<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised', window );">Exercise of stock options and warrants</a></td>
<td class="nump">54<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">54<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">1,262<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,262<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="num">(3)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(3)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(16,246)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(16,246)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Dec. 31, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">45,388,023<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Dec. 31, 2019</a></td>
<td class="nump">78,318<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">270,662<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">25<span></span>
</td>
<td class="num">(192,374)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercise of stock options (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">43,055<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised', window );">Exercise of stock options</a></td>
<td class="nump">$ 119<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">119<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised', window );">Exercise of common stock warrant in exchange for common stock (in shares)</a></td>
<td class="nump">0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2,574,971<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">$ 1,609<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,609<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="num">(29)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(29)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(16,926)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(16,926)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Mar. 31, 2020</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">48,006,049<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Mar. 31, 2020</a></td>
<td class="nump">63,091<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">272,390<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(4)<span></span>
</td>
<td class="num">(209,300)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at beginning of period (in shares) at Dec. 31, 2019</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">45,388,023<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at beginning of period at Dec. 31, 2019</a></td>
<td class="nump">$ 78,318<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">270,662<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">25<span></span>
</td>
<td class="num">(192,374)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercise of stock options (in shares)</a></td>
<td class="nump">338,069<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">$ (59,203)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Sep. 30, 2020</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">68,470,081<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Sep. 30, 2020</a></td>
<td class="nump">253,308<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 7<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">504,876<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
<td class="num">(251,575)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at beginning of period (in shares) at Mar. 31, 2020</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">48,006,049<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at beginning of period at Mar. 31, 2020</a></td>
<td class="nump">63,091<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">272,390<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(4)<span></span>
</td>
<td class="num">(209,300)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercise of stock options (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">206,143<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised', window );">Exercise of stock options</a></td>
<td class="nump">1,296<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,296<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Issuance of common stock under public offering, net of issuance costs (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">10,900,599<span></span>
</td>
<td class="nump">9,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueNewIssues', window );">Issuance of common stock under public offering, net of issuance costs</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 62,977<span></span>
</td>
<td class="nump">$ 163,991<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 1<span></span>
</td>
<td class="nump">$ 1<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 62,976<span></span>
</td>
<td class="nump">$ 163,990<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans', window );">Purchase of common stock under ESPP (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">68,419<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition', window );">Purchase of common stock under ESPP</a></td>
<td class="nump">333<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">333<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">1,656<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,656<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="nump">6<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">6<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(19,786)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(19,786)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Jun. 30, 2020</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">68,381,210<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Jun. 30, 2020</a></td>
<td class="nump">273,564<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 7<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">502,641<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2<span></span>
</td>
<td class="num">(229,086)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward', window );"><strong>Increase (Decrease) in Stockholders' Equity</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercise of stock options (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">88,871<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised', window );">Exercise of stock options</a></td>
<td class="nump">317<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">317<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue', window );">Stock-based compensation expense</a></td>
<td class="nump">1,918<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,918<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax', window );">Other comprehensive income (loss)</a></td>
<td class="num">(2)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(2)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net (loss) income</a></td>
<td class="num">(22,489)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(22,489)<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesOutstanding', window );">Balance at end of period (in shares) at Sep. 30, 2020</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">68,470,081<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rc">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquity', window );">Balance at end of period at Sep. 30, 2020</a></td>
<td class="nump">$ 253,308<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 7<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 504,876<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="num">$ (251,575)<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares issued during period and exercise of common stock warrant in exchange for common stock</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_StockIssuedDuringPeriodSharesOfCommonStockWarrantsInExchangeForCommonStockExercised</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of stock issued as a result of the exercise of stock options and warrants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_StockIssuedDuringPeriodSharesStockOptionsAndWarrantsExercised</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Value of stock issued as a result of the exercise of stock options and warrants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_StockIssuedDuringPeriodValueStockOptionsAndWarrantsExercised</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of stock that have been retired in exchange for common stock warrant</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantShares</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantValue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Equity impact of the value of stock that has been retired in exchange for common stock warrant.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_StockRetiredDuringPeriodExchangedForCommonStockWarrantValue</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase in additional paid-in capital (APIC) for recognition of cost for employee stock purchase program (ESPP) award under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationEmployeeStockPurchaseProgramRequisiteServicePeriodRecognition</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase to additional paid-in capital (APIC) for recognition of cost for award under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 20<br> -Section 55<br> -Paragraph 12<br> -URI http://asc.fasb.org/extlink&amp;oid=120383193&amp;loc=d3e11149-113907<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5047-113901<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 20<br> -Section 55<br> -Paragraph 13<br> -URI http://asc.fasb.org/extlink&amp;oid=120383193&amp;loc=d3e11178-113907<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 35<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=121326096&amp;loc=d3e4534-113899<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase in additional paid in capital (APIC) resulting from the issuance of warrants. Includes allocation of proceeds of debt securities issued with detachable stock purchase warrants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 20<br> -Section 25<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109126253&amp;loc=d3e4724-112606<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInStockholdersEquityRollForward</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetIncomeLoss">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1A<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669619-108580<br><br>Reference 2: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 31<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8924-108599<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 11<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22694-107794<br><br>Reference 4: 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-SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 18: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22583-107794<br><br>Reference 19: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 20: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 45<br> -Paragraph 60B<br> -Subparagraph (a)<br> -URI 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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetIncomeLoss</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherComprehensiveIncomeLossNetOfTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount after tax and reclassification adjustments of other comprehensive income (loss).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1A<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669619-108580<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 830<br> -SubTopic 30<br> -Section 45<br> -Paragraph 17<br> -URI http://asc.fasb.org/extlink&amp;oid=118261656&amp;loc=d3e32136-110900<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SX 210.5-03(21))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 55<br> -Paragraph 15<br> -URI http://asc.fasb.org/extlink&amp;oid=121640130&amp;loc=d3e1436-108581<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 830<br> -SubTopic 30<br> -Section 45<br> -Paragraph 20<br> -URI http://asc.fasb.org/extlink&amp;oid=118261656&amp;loc=d3e32211-110900<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 830<br> -SubTopic 30<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6450520&amp;loc=d3e32583-110901<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1B<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669625-108580<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 220<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-04(23))<br> -URI http://asc.fasb.org/extlink&amp;oid=120399700&amp;loc=SL114874048-224260<br><br>Reference 10: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 220<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-04(19))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400993&amp;loc=SL114874131-224263<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherComprehensiveIncomeLossNetOfTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SharesOutstanding">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares issued which are neither cancelled nor held in the treasury.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SharesOutstanding</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares issued during the period as a result of an employee stock purchase plan.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of new stock issued during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of share options (or share units) exercised during the current period.</p></div>
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<tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Value of stock issued as a result of the exercise of stock options.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.29-31)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 310<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SAB Topic 4.E)<br> -URI http://asc.fasb.org/extlink&amp;oid=27010918&amp;loc=d3e74512-122707<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(31))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(30))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 825<br> -SubTopic 10<br> -Section 50<br> -Paragraph 28<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=75031198&amp;loc=d3e14064-108612<br><br>Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982305384">
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<th class="th"><div>Jun. 30, 2020</div></th>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Discounts and commissions deducted from cash proceeds received on stock transaction.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217984032520">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Condensed Consolidated Statements of Cash Flows - USD ($)<br> $ in Thousands</strong></div></th>
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<th class="th"><div>Sep. 30, 2020</div></th>
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</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract', window );"><strong>Cash flows from operating activities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProfitLoss', window );">Net loss</a></td>
<td class="num">$ (59,203)<span></span>
</td>
<td class="num">$ (11,962)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract', window );"><strong>Adjustments to reconcile net loss to net cash used in operating activities:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DepreciationDepletionAndAmortization', window );">Depreciation</a></td>
<td class="nump">750<span></span>
</td>
<td class="nump">963<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments', window );">Net amortization of premiums and discounts on investments</a></td>
<td class="num">(86)<span></span>
</td>
<td class="num">(87)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensation', window );">Stock-based compensation</a></td>
<td class="nump">5,183<span></span>
</td>
<td class="nump">3,610<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherNoncashIncomeExpense', window );">Other non-cash items</a></td>
<td class="nump">110<span></span>
</td>
<td class="nump">65<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract', window );"><strong>Changes in operating assets and liabilities:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInAccountsReceivable', window );">Accounts receivable</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">161<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets', window );">Prepaid expenses and other current assets</a></td>
<td class="num">(2,460)<span></span>
</td>
<td class="nump">1,318<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInOtherOperatingAssets', window );">Other assets</a></td>
<td class="num">(700)<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInAccountsPayable', window );">Accounts payable</a></td>
<td class="num">(2,766)<span></span>
</td>
<td class="num">(3,102)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInAccruedLiabilities', window );">Accrued expenses</a></td>
<td class="nump">2,367<span></span>
</td>
<td class="num">(4,518)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_IncreaseDecreaseInOperatingLeaseAssets', window );">Operating lease assets</a></td>
<td class="nump">1,235<span></span>
</td>
<td class="nump">1,290<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities', window );">Operating lease liabilities</a></td>
<td class="num">(990)<span></span>
</td>
<td class="num">(1,356)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncreaseDecreaseInContractWithCustomerLiability', window );">Deferred revenue</a></td>
<td class="num">(817)<span></span>
</td>
<td class="num">(41,550)<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInOperatingActivities', window );">Net cash used in operating activities</a></td>
<td class="num">(57,377)<span></span>
</td>
<td class="num">(55,168)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract', window );"><strong>Cash flows from investing activities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities', window );">Maturities of marketable securities</a></td>
<td class="nump">37,500<span></span>
</td>
<td class="nump">10,500<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt', window );">Purchase of marketable securities</a></td>
<td class="nump">0<span></span>
</td>
<td class="num">(53,688)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment', window );">Purchase of property and equipment</a></td>
<td class="num">(285)<span></span>
</td>
<td class="num">(605)<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInInvestingActivities', window );">Net cash provided by (used in) investing activities</a></td>
<td class="nump">37,215<span></span>
</td>
<td class="num">(43,793)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract', window );"><strong>Cash flows from financing activities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromStockOptionsExercised', window );">Proceeds from exercise of stock options</a></td>
<td class="nump">1,732<span></span>
</td>
<td class="nump">121<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans', window );">Proceeds from purchases of common stock under ESPP</a></td>
<td class="nump">333<span></span>
</td>
<td class="nump">283<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ProceedsFromDebtNetIssuanceCosts', window );">Proceeds from issuance of debt, net of issuance costs</a></td>
<td class="num">(197)<span></span>
</td>
<td class="nump">4,965<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeasePrincipalPayments', window );">Payments under capital lease obligations</a></td>
<td class="num">(87)<span></span>
</td>
<td class="num">(58)<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInFinancingActivities', window );">Net cash provided by financing activities</a></td>
<td class="nump">228,747<span></span>
</td>
<td class="nump">97,473<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect', window );">Increase (decrease) in cash, cash equivalents and restricted cash</a></td>
<td class="nump">208,585<span></span>
</td>
<td class="num">(1,488)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents', window );">Cash, cash equivalents and restricted cash, beginning of period</a></td>
<td class="nump">62,672<span></span>
</td>
<td class="nump">60,005<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents', window );">Cash, cash equivalents and restricted cash, end of period</a></td>
<td class="nump">271,257<span></span>
</td>
<td class="nump">58,517<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SupplementalCashFlowInformationAbstract', window );"><strong>Supplemental disclosures of non-cash activities:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction', window );">Debt financing costs in accrued expenses</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">180<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_InterestPaidNet', window );">Cash paid for interest</a></td>
<td class="nump">173<span></span>
</td>
<td class="nump">64<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability', window );">Right-of-use assets obtained in exchange for operating lease liabilities</a></td>
<td class="nump">9,980<span></span>
</td>
<td class="nump">4,778<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability', window );">Right-of-use assets obtained in exchange for financing lease liabilities</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">429<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember', window );">Public Stock Offering</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract', window );"><strong>Cash flows from financing activities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromIssuanceOfCommonStock', window );">Net proceeds from public offering of common stock</a></td>
<td class="nump">163,990<span></span>
</td>
<td class="nump">92,162<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2018ATMMember', window );">ATM</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract', window );"><strong>Cash flows from financing activities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromIssuanceOfCommonStock', window );">Net proceeds from public offering of common stock</a></td>
<td class="nump">$ 62,976<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_IncreaseDecreaseInOperatingLeaseAssets">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The increase (decrease) during the reporting period in operating lease assets</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_IncreaseDecreaseInOperatingLeaseAssets</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_IncreaseDecreaseInOperatingLeaseLiabilities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The increase (decrease) during the reporting period in operating lease liabilities</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_IncreaseDecreaseInOperatingLeaseLiabilities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ProceedsFromDebtNetIssuanceCosts">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The cash inflow (outflow) during the period from borrowings in aggregate debt. Includes proceeds from short-term and long-term debt and delayed cash payments of issuance costs.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ProceedsFromDebtNetIssuanceCosts</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 24<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3521-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 4<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3044-108585<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=SL98516268-108586<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase (decrease) in cash, cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; including effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 830<br> -SubTopic 230<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=98513438&amp;loc=d3e33268-110906<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 24<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3521-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The amount of debt issuance costs that were incurred during a noncash or partial noncash transaction.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=d3e4304-108586<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 4<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=d3e4313-108586<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=d3e4332-108586<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DepreciationDepletionAndAmortization">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (e)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DepreciationDepletionAndAmortization</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeasePrincipalPayments">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash outflow for principal payment on finance lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 45<br> -Paragraph 5<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121603541&amp;loc=SL77918643-209977<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (g)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918686-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeasePrincipalPayments</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInAccountsPayable">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The increase (decrease) during the reporting period in the aggregate amount of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInAccountsPayable</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInAccountsReceivable">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The increase (decrease) during the reporting period in amount due within one year (or one business cycle) from customers for the credit sale of goods and services.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInAccountsReceivable</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInAccruedLiabilities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The increase (decrease) during the reporting period in the aggregate amount of expenses incurred but not yet paid.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInAccruedLiabilities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInContractWithCustomerLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInContractWithCustomerLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInOperatingCapitalAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInOtherOperatingAssets">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase (decrease) in operating assets classified as other.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInOtherOperatingAssets</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase (decrease) in prepaid expenses, and assets classified as other.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
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</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_InterestPaidNet">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=d3e4297-108586<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 17<br> -Subparagraph (d)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3367-108585<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 25<br> -Subparagraph (e)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3536-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_InterestPaidNet</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetCashProvidedByUsedInFinancingActivities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 24<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3521-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetCashProvidedByUsedInFinancingActivities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetCashProvidedByUsedInInvestingActivities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 24<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3521-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetCashProvidedByUsedInInvestingActivities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetCashProvidedByUsedInOperatingActivities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 25<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3536-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 24<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3521-108585<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetCashProvidedByUsedInOperatingActivities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherNoncashIncomeExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of income (expense) included in net income that results in no cash inflow (outflow), classified as other.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherNoncashIncomeExpense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash outflow to acquire investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 13<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3213-108585<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 11<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3151-108585<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 45<br> -Paragraph 11<br> -URI http://asc.fasb.org/extlink&amp;oid=121553693&amp;loc=d3e26853-111562<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 13<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3213-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PaymentsToAcquirePropertyPlantAndEquipment</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProceedsFromIssuanceOfCommonStock">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The cash inflow from the additional capital contribution to the entity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3255-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProceedsFromIssuanceOfCommonStock</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow from issuance of shares under share-based payment arrangement. Excludes option exercised.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3255-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2A<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=SL79508275-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow from maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 45<br> -Paragraph 11<br> -URI http://asc.fasb.org/extlink&amp;oid=121553693&amp;loc=d3e26853-111562<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 11<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3151-108585<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 12<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3179-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProceedsFromStockOptionsExercised">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow from exercise of option under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2A<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=SL79508275-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3255-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProceedsFromStockOptionsExercised</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProfitLoss">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08(g)(1)(ii))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1A<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121641772&amp;loc=SL7669619-108580<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 205<br> -SubTopic 20<br> -Section 50<br> -Paragraph 7<br> -URI 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-Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 45<br> -Paragraph 19<br> -URI http://asc.fasb.org/extlink&amp;oid=108774443&amp;loc=SL4569616-111683<br><br>Reference 18: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 323<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=114001798&amp;loc=d3e33918-111571<br><br>Reference 19: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (f)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 20: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 810<br> -SubTopic 10<br> -Section 55<br> -Paragraph 4K<br> -URI http://asc.fasb.org/extlink&amp;oid=120409616&amp;loc=SL4591552-111686<br><br>Reference 21: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 250<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=109234566&amp;loc=d3e22658-107794<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProfitLoss</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase in right-of-use asset obtained in exchange for finance lease liability.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 55<br> -Paragraph 53<br> -URI http://asc.fasb.org/extlink&amp;oid=121568110&amp;loc=SL77918982-209971<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (g)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918686-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase in right-of-use asset obtained in exchange for operating lease liability.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 55<br> -Paragraph 53<br> -URI http://asc.fasb.org/extlink&amp;oid=121568110&amp;loc=SL77918982-209971<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (g)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918686-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensation">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of noncash expense for share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 28<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3602-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensation</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SupplementalCashFlowInformationAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SupplementalCashFlowInformationAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980576232">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Nature of business and basis of presentation<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract', window );"><strong>Organization, Consolidation and Presentation of Financial Statements [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock', window );">Nature of business and basis of presentation</a></td>
<td class="text">Nature of business and basis of presentation<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Mersana Therapeutics, Inc. is a clinical stage biopharmaceutical company focused on developing antibody drug conjugates (ADCs) that offer a clinically meaningful benefit for cancer patients with significant unmet need. The Company has leveraged 20&#160;years of industry learning in the ADC field to develop proprietary and differentiated technology platforms that enable it to design ADCs to have improved efficacy, safety and tolerability relative to existing ADC therapies. The Company&#8217;s innovative platforms, which include Dolaflexin and Dolasynthen, each delivering its DolaLock payload, as well as Immunosynthen, delivering a novel stimulator of interferon genes (STING) agonist, provide an efficient product engine that has enabled a robust discovery pipeline for the Company and its partners. The Company&#8217;s product candidates include XMT-1536 and XMT-1592. The Company's early stage programs include a potentially first-in-class B7-H4-targeted DolaLock ADC as well as candidates leveraging the Immunosynthen platform. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">XMT-1536, an ADC utilizing the Company&#8217;s Dolaflexin platform and targeting NaPi2b, an antigen broadly expressed in ovarian cancer and non-small cell lung cancer (NSCLC) adenocarcinoma, is currently in the expansion portion of a Phase 1 study in patients with ovarian cancer and NSCLC adenocarcinoma. XMT-1592 uses one of the Company&#8217;s new platforms, Dolasynthen, and also targets NaPi2b. The Company filed an Investigational New Drug (IND) application in the first quarter of 2020 and initiated the Phase 1 dose escalation study of XMT-1592 in the second quarter of 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company has incurred cumulative net losses since inception. For the nine months ended September&#160;30, 2020, the net loss was $59,203, compared to net loss of $11,962 in the nine months ended September&#160;30, 2019. The difference year over year is primarily attributable to $39,965 in deferred revenue that was recognized in the first quarter of 2019 as a result of the discontinuation of the partnership with Takeda in that quarter. The Company expects to continue to incur operating losses for at least the next several years. As of September&#160;30, 2020, the Company had an accumulated deficit of $251,575. The future success of the Company is dependent on, among other factors, its ability to identify and develop its product candidates and ultimately upon its ability to attain profitable operations. The Company has devoted substantially all of its financial resources and efforts to research and development and general and administrative expense to support such research and development. Net losses and negative operating cash flows have had, and will continue to have, an adverse effect on the Company&#8217;s stockholders' equity and working&#160;capital.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In April 2020, the Company sold 10,900,599 shares of common stock and received net proceeds of $62,976. In addition, in June 2020, the Company sold 9,200,000 shares of common stock and received net proceeds of $163,991. The Company believes that its currently available funds will be sufficient to fund the Company&#8217;s operations through at least the next twelve months from the issuance of this Quarterly Report on Form 10-Q. Management&#8217;s belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management&#8217;s estimates, the Company may need to seek additional funding.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, the need for additional capital, risks of failure of preclinical and clinical studies, the need to obtain marketing approval and reimbursement for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development of technological innovations by competitors, reliance on third party manufacturers and the ability to transition from pilot-scale production to large-scale manufacturing of products.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company&#8217;s unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S.&#160;GAAP) and the rules and regulations of the Securities and Exchange Commission (SEC). Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Updates (ASU) of the Financial Accounting Standards Board (FASB). All dollar amounts, except per share data in the text and tables herein, are stated in thousands unless otherwise indicated. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December&#160;31, 2019 and the notes thereto, included in the Company&#8217;s Annual Report on Form 10-K for the year ended December&#160;31, 2019 filed with the SEC on February 28, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited financial statements. In the opinion of the Company&#8217;s management, the accompanying unaudited condensed consolidated financial statements contain all adjustments that are necessary to present fairly the Company&#8217;s financial position as of September&#160;30, 2020, the results of its operations for the three and nine months ended September&#160;30, 2020 and 2019, a statement of stockholders&#8217; equity for the three and nine months ended September&#160;30, 2020 and 2019 and cash flows for the nine months ended September&#160;30, 2020 and 2019. Such adjustments are of a normal and recurring nature. The results for the three and nine months ended September&#160;30, 2020 are not necessarily indicative of the results for the year ending December&#160;31, 2020, or for any future period.</span></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for the business description and basis of presentation concepts.  Business description describes the nature and type of organization including but not limited to organizational structure as may be applicable to holding companies, parent and subsidiary relationships, business divisions, business units, business segments, affiliates and information about significant ownership of the reporting entity.  Basis of presentation describes the underlying basis used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -URI http://asc.fasb.org/topic&amp;trid=2122369<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 205<br> -URI http://asc.fasb.org/topic&amp;trid=2122149<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 275<br> -URI http://asc.fasb.org/topic&amp;trid=2134479<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217996838840">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Summary of Significant Accounting Policies<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccountingPoliciesAbstract', window );"><strong>Accounting Policies [Abstract]</strong></a></td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SignificantAccountingPoliciesTextBlock', window );">Summary of Significant Accounting Policies</a></td>
<td class="text">Summary of Significant Accounting Policies<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Principles of Consolidation</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The accompanying unaudited condensed consolidated financial statements include those of the Company and its wholly owned subsidiary, Mersana Securities Corp. All intercompany balances and transactions have been eliminated.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of the Company&#8217;s unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company&#8217;s management evaluates its estimates which include, but are not limited to, management&#8217;s judgments with respect to the identification of performance obligations and standalone selling prices of those performance obligations within its revenue arrangements, accrued expenses, valuation of stock-based awards and income taxes. Actual results could differ from those estimates.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Segment Information</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker, or decision making group, in deciding how to allocate resources and assess performance. The Company views its operations and manages its business as a single operating segment, which is the business of discovering and developing ADCs.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Summary of Accounting Policies</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and nine months ended September&#160;30, 2020 are consistent with those discussed in Note 2 to the consolidated financial statements in the Company&#8217;s 2019 Annual Report on Form 10-K, except as otherwise noted below in "Recently Issued Accounting Pronouncements."</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Fair Value Measurements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. ASC Topic&#160;820&#160;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Fair Value Measurement</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#160;(ASC&#160;820) establishes a three-level valuation hierarchy for instruments measured at fair value. The hierarchy is based on the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows:</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Level&#160;1&#8212;Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Level&#160;2&#8212;Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Level&#160;3&#8212;Inputs to the valuation methodology are unobservable and significant to the fair value measurement.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Cash and Cash Equivalents</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company considers all highly liquid investments with an original maturity, or a remaining maturity at the time of purchase, of three months or less to be cash equivalents. The Company invests excess cash primarily in money market funds, commercial paper and government agency securities, which are highly liquid and have strong credit ratings. These investments are subject to minimal credit and market risks. Cash and cash equivalents are stated at cost, which approximates market value.</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30, 2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30, 2019</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning<br/>of period</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">End<br/>of period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning<br/>of period</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">End<br/>of period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash and cash equivalents</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">62,351&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">270,936&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">59,634&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">58,196&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted cash included in other assets, noncurrent</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">371&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total cash, cash equivalents and restricted cash per statement of cash flows</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">62,672&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">271,257&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">60,005&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">58,517&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Marketable Securities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Short-term marketable securities consist of investments in debt securities with maturities greater than three months and less than one year from the balance sheet date. The Company classifies all of its marketable securities as available-for-sale. Accordingly, these investments are recorded at fair value. Amortization and accretion of discounts and premiums are recorded as interest income within other income. Prior to the adoption of ASU 2016-13,</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"> Financial Instruments - Credit Losses</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, unrealized gains and losses on available-for-sale securities are included in other accumulated comprehensive income (loss) as a component of stockholders&#8217; equity until realized. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other income (expense), net, based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers various factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. Fair value is determined based on quoted market prices.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Other Assets</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company recorded other assets of $2,153 and $1,453 as of September&#160;30, 2020 and December&#160;31, 2019, respectively, comprised of $1,832 and $1,132, respectively, held by a service provider, and restricted cash of $321 at the end of each period held as security deposits for a standby letter of credit related to a facility lease. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Net Loss per Share</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without further consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury stock and if-converted methods.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For purposes of the diluted net loss per share calculation, stock options, unvested restricted stock units (RSUs), warrants to purchase common stock and options to purchase common stock are considered to be potentially dilutive securities, but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table sets forth the outstanding potentially dilutive securities that have been excluded from the calculation of diluted net loss per share for the three and nine months ended September&#160;30, 2020 and 2019, because to include them would be anti-dilutive (in common stock equivalent shares):</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"> </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:49.541%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:23.258%"/><td style="width:0.1%"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td style="width:0.1%"/><td style="width:0.441%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:23.260%"/><td style="width:0.1%"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three and Nine Months Ended<br/>September 30, 2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three and Nine Months Ended<br/>September 30, 2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,215,368&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,718,597&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested restricted stock units</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">740,862&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">447,336&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Warrants</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,995,704&#160;</span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,205,407&#160;</span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Recently Issued Accounting Pronouncements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In November 2018, the FASB issued ASU No. 2018-18, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. The main provisions of ASU 2018-18 include: (i) clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue when the collaborative arrangement participant is a customer in the context of a unit of account and (ii) precluding the presentation of transactions with collaborative arrangement participants that are not directly related to sales to third parties together with revenue. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The guidance per ASU 2018-18 is to be adopted retrospectively to the date of initial application of Topic 606. The Company adopted the new standard effective January 1, 2020. The adoption of this standard did not have a material impact on the Company&#8217;s consolidated financial statements and related disclosures.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2016, the FASB issued ASU 2016-13, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, which requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. Historically, U.S. GAAP delayed recognition of the full amount of credit losses until the loss was probable of occurring. Under this ASU, the income statement will reflect an entity&#8217;s current estimate of all expected credit losses. The measurement of expected credit losses will be based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down of the security. This ASU is effective for annual periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The Company adopted the new standard effective January 1, 2020 using the modified retrospective method. The adoption of this standard did not have a material impact on the Company&#8217;s consolidated financial statements and related disclosures.</span></div><span></span>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982479128">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationAgreementsAbstract', window );"><strong>Collaboration agreements</strong></a></td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementDisclosureTextBlock', window );">Collaboration agreements</a></td>
<td class="text">Collaboration agreements<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Merck KGaA</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2014, the Company entered into a Collaboration and Commercial License Agreement with Merck KGaA (the Merck KGaA Agreement). Upon the execution of the agreement, Merck KGaA paid the Company a nonrefundable technology access fee of $12,000 for the right to develop ADCs directed to six exclusive targets over a specified period of time. No additional fees are due when a target is designated and the commercial license to the target is granted. Merck KGaA will be responsible for the product development and marketing of any products resulting from this collaboration.&#160;All six targets were designated prior to 2018. The Company is eligible to receive milestones under the Merck KGaA Agreement. The next potential milestone payment is a development milestone of $500 on Merck KGaA&#8217;s designation of a preclinical development candidate for a target. Revenue for the milestone is fully constrained until it is certain the milestone would be achieved.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Under the terms of the Merck KGaA Agreement, the Company and Merck KGaA develop research plans to evaluate Merck KGaA's antibodies as ADCs incorporating the Company's technology. The Company receives reimbursement for its efforts under the research plans. The goal of the research plans is to provide Merck KGaA with sufficient information to formally nominate a development candidate and begin IND-enabling studies or cease development on the designated target.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In May 2018, the Company entered into a Supply Agreement with Merck KGaA (the Merck KGaA Supply Agreement). Under the terms of the Merck KGaA Supply Agreement, the Company will provide Merck KGaA preclinical non-GMP ADC Drug Substance and clinical GMP Drug Substance for use in clinical trials associated with one of the antibodies designated under the Merck KGaA Agreement. The Company receives fees for its efforts under the Merck KGaA Supply Agreement and reimbursement equal to the supply cost. The Company may also enter into future supply agreements to provide clinical supply material should Merck KGaA pursue clinical development of any other candidates nominated under the Merck KGaA Agreement.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Accounting Analysis</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company identified the following performance obligations under the Merck KGaA agreement: (i) exclusive license and research services for six designated targets, (ii) rights to future technological improvements and (iii) participation of project team leaders and providing joint research committee services.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company is recognizing revenue related to the exclusive license and research and development services over the estimated period of the research and development services using a proportional performance model.  The Company measures proportional performance based on the costs incurred relative to the total costs expected to be incurred. To the extent that the Company receives fees for the research services as they are performed, these amounts are recorded as deferred revenue. Revenue related to future technological improvements and joint research committee services will be recognized ratably over the respective performance period (which in the case of the joint research committee services approximates the time and cost incurred each period), which are 10 and five years, respectively.&#160;The Company is continuing to reassess the estimated remaining term at each subsequent reporting period. As of December 31, 2019, the total transaction price for the Merck KGaA Agreement was $21,500, which represented the amount of consideration the Company was expected to receive for the transfer of goods and services to Merck KGaA. During the nine months ended September&#160;30, 2020, the Company decreased the fees expected to be received for research and development activities by $175 to $6,325, resulting in a revised total transaction price for the Merck KGaA Agreement of $21,325.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the nine months ended September&#160;30, 2020, the Company completed its performance obligations associated with one of the six designated targets. For the three months ended September&#160;30, 2020 and 2019, and the nine months ended September&#160;30, 2020 and 2019, the Company recorded collaboration revenue of $11, $800, $817, and $836, respectively, related to its efforts under the Merck KGaA Agreement. During the three and nine months ended </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2019, the Company recognized $34 and $1,255, respectively, in collaboration revenue and corresponding research and development expense of $34 and $1,255, respectively, related to the Merck KGaA Supply Agreement.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020 and December&#160;31, 2019, the Company had $3,998 and $4,815, respectively, in deferred revenue related to the Merck KGaA Agreement and Merck KGaA Supply Agreement that will be recognized over the remaining performance period.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Takeda XMT-1522 Strategic Partnership</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In January 2016, the Company entered into a Development Collaboration and Commercial License Agreement with Takeda's wholly owned subsidiary, Millennium Pharmaceuticals, Inc. for the development and commercialization of XMT-1522 (the XMT-1522 Agreement). Under the XMT-1522 Agreement, Takeda was granted the exclusive right to commercialize XMT-1522 outside of the United States and Canada. Under the XMT-1522 Agreement, the Company was responsible for conducting certain Phase 1 development activities for XMT-1522, including the ongoing Phase 1 clinical trial, at its own expense. The parties agreed to collaborate on the further development of XMT-1522 in accordance with a global development plan (Post-Phase 1 Development). On January 2, 2019, the Company received notice from Takeda stating that Takeda was exercising its right to terminate the XMT-1522 Agreement upon 30 days&#8217; prior written notice. The XMT-1522 Agreement terminated in accordance with its provisions, and the Company and Takeda wound down activities related to the XMT-1522 Agreement as of March 31, 2019. Under the XMT-1522 Agreement, the Company and Takeda shared equally all budgeted Post-Phase 1 Development costs through the date of termination and for a period of 30 days after the effective termination date.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">For the applicable period within the three months ended March 31, 2019, the Company was billed $200 by Takeda, representing the Company&#8217;s share of Post-Phase 1 Development costs incurred by Takeda. This amount has been reflected as research and development costs in the consolidated statement of operations.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Takeda strategic research and development partnership</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In March 2014, the Company entered into a Research Collaboration and Commercial License Agreement with Takeda through Takeda&#8217;s wholly owned subsidiary, Millennium Pharmaceuticals, Inc. (the 2014 Agreement). The 2014 Agreement was amended in January 2015 and amended and restated in January 2016 (the 2016 Restated Agreement). The agreements provided Takeda with the right to develop ADCs directed to a total of seven exclusive targets, designated by Takeda, over a specified period of time. On January 2, 2019, the Company received notice from Takeda stating that Takeda was exercising its right to terminate the 2016 Restated Agreement upon 45 days&#8217; prior written notice. The 2016 Restated Agreement terminated in accordance with its provisions, and the Company and Takeda wound down activities related to the 2016 Restated Agreement as of March 31, 2019.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the applicable period within the three months ended March 31, 2019, the Company billed Takeda $195 related to ASC 808 costs.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Accounting Analysis</span></div><div style="margin-bottom:12pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company&#8217;s collaboration agreements with Takeda were terminated following receipt of written notices during the first quarter of 2019. As there are no further performance obligations, the Company recognized the remaining deferred revenue of</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> $39,965 </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">related to the termination of the Takeda agreements in the</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> first quarter of 2019.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Included in accounts payable as of September&#160;30, 2020 and December&#160;31, 2019 was $2,335 related to the Takeda agreements.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Summary of Contract Assets and Liabilities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents changes in the balances of our contract assets and liabilities during the nine months ended September&#160;30, 2020 and 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>Beginning<br/>of Period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Additions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Deductions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>End of Period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Nine months ended September 30, 2020</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract assets</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract liabilities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,815&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">817&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,998&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span><br/></span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>Beginning<br/>of Period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Additions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Deductions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>End of Period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Nine months ended September 30, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract assets</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract liabilities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">46,196&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">41,550&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,646&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the three and nine months ended September&#160;30, 2020 and 2019, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Revenue recognized in the period from:</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Amounts included in the contract liability at the beginning of the period</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">834&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">817&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">41,550&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Performance obligations satisfied in previous periods</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Other Revenue</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company has provided limited services for a collaboration partner, Asana BioSciences. For the three and nine months ended September&#160;30, 2019, the Company recognized $10 and $25, respectively, of revenue related to these services. The Company did not recognize any revenue related to these services for the three and nine months ended September&#160;30, 2020. The next potential milestone the Company is eligible to receive is $2,500 upon dosing the fifth patient in a Phase 1 clinical study by Asana BioSciences. As of September&#160;30, 2020, the Company considers this next milestone to be fully constrained as there is considerable judgment involved in determining whether it is probable that a significant revenue reversal would occur. As part of its evaluation of the constraint, the Company considered numerous factors, including the fact that achievement of the milestone is outside the control of the Company and there is a high level of uncertainty in achieving this milestone, as this would require successful initiation of clinical trials by the collaboration partner. The Company reevaluates the probability of achievement of a milestone subject to constraint at each reporting period and as uncertain events are resolved or other changes in circumstances occur.</span></div><span></span>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980815128">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Fair value measurements<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueDisclosuresAbstract', window );"><strong>Fair Value Disclosures [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="text">Fair value measurements<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents information about the Company's assets and liabilities regularly measured and carried at a fair value and indicates the level within fair value hierarchy of the valuation techniques utilized to determine such value as of December&#160;31, 2019. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company had no marketable securities as of </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2020</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">: </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Fair<br/>Value</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Quoted&#160;Prices<br/>in&#160;Active<br/>Markets<br/>(Level&#160;1)</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Significant<br/>Other<br/>Observable<br/>Inputs<br/>(Level&#160;2)</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Significant<br/>Unobservable<br/>Inputs<br/>(Level&#160;3)</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Marketable securities:</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Commercial paper</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Corporate bonds</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">12,010&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">12,010&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">U.S. Treasuries</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,439&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">23,950&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">There were no changes in valuation techniques or transfers between fair value measurement levels during the nine months ended September&#160;30, 2020 and 2019. </span></div><div style="margin-bottom:12pt"><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The carrying amounts reflected in the consolidated balance sheets for prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values due to their short-term nature.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, the carrying value of the Company&#8217;s outstanding borrowing under the Amended Credit Facility (as defined below) approximated fair value (a Level 2 fair value measurement), reflecting interest rates currently available to the Company. The Amended Credit Facility is discussed in more detail in Note 7, &#8220;Debt&#8221;.</span></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure of the fair value measurement of assets and liabilities, which includes financial instruments measured at fair value that are classified in shareholders' equity, which may be measured on a recurring or nonrecurring basis.</p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982453416">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Marketable securities<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_MarketableSecuritiesAbstract', window );"><strong>Marketable Securities [Abstract]</strong></a></td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock', window );">Marketable securities</a></td>
<td class="text">Marketable securities<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table summarizes marketable securities held at December&#160;31, 2019. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company had no marketable securities as of </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2020</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">: </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Amortized<br/>Cost</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Gross<br/>Unrealized<br/>Gains</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Gross<br/>Unrealized<br/>Losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Fair<br/>Value</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Commercial paper</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Corporate bonds</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,990&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">20&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">12,010&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">U.S. Treasuries</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,484&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,414&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">25&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,439&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for  investments in certain debt and equity securities.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 320<br> -URI http://asc.fasb.org/subtopic&amp;trid=2209399<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 946<br> -SubTopic 320<br> -URI http://asc.fasb.org/subtopic&amp;trid=2324412<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -URI http://asc.fasb.org/topic&amp;trid=2196928<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 940<br> -SubTopic 320<br> -URI http://asc.fasb.org/subtopic&amp;trid=2176304<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217996838840">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Accrued Expenses<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="text">&#160;<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock', window );">Accrued expenses</a></td>
<td class="text">Accrued expenses<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Accrued expenses consisted of the following as of September&#160;30, 2020 and December&#160;31, 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued payroll and related expenses</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,647&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,037&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued preclinical, manufacturing and clinical expenses</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,600&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,230&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued professional fees and insurance</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">861&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">675&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued other</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">65&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">44&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,173&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">8,986&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for accounts payable and accrued liabilities at the end of the reporting period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.19(a),20,24)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982453416">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Debt<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtDisclosureAbstract', window );"><strong>Debt Disclosure [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
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<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtDisclosureTextBlock', window );">Debt</a></td>
<td class="text">Debt<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On May 8, 2019, the Company entered into a loan and security agreement (the Original Agreement) with Silicon Valley Bank (SVB) pursuant to which the Company borrowed $5,000. The Original Agreement accrued interest at a floating per annum rate equal to the greater of (i) 4.0% and (ii) 1.50% below the Prime Rate. The Original Agreement had an interest-only period through August 31, 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On August 28, 2020 (the Effective Date), the Company entered into a second amendment (the Amendment)</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> to its existing loan and security agreement (as amended prior to the Amendment, the Existing Credit Facility) with </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">SVB. Pursuant to the Amendment, the Company can borrow term loans in an aggregate amount of $30,000 (the Amended Credit Facility), at its option, </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">(i) up to $25,000 in up to five principal advances through April 30, 2022, and (ii) an additional $5,000 in one principal advance, if the Company reaches certain development milestone events, as described in the Amendment, through April 30, 2022. The Company drew $5,200 upon execution of the Amendment, the proceeds of which were used to repay the Company&#8217;s existing balance and satisfy its obligations to SVB, including the final payment obligation under the Existing Credit Facility.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Amended Credit Facility bears interest at a floating per annum rate equal to the greater of (i) 4.25% and (ii) 1.00% above the Prime Rate, as defined. The Company is obligated to make monthly interest-only payments on each outstanding term loan commencing on the first calendar day of the month following the funding date of such term loan, and continuing on the first calendar day of each month thereafter through May 31, 2022. The interest only period may be extended through January 31, 2023 upon the achievement of a regulatory milestone, as described in the Amendment. Following the interest-only period, the Company will be required to repay the outstanding principal balance under the term loans in equal monthly payments plus interest in arrears to SVB through November 1, 2024 (the Maturity Date).</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company is also required to make a final payment to SVB equal to 5.5% of the original principal amount of the term loans then extended to the Company. This final payment is accreted under the effective interest method over the life of each term loan. The term loans are secured by substantially all of the Company's assets, except for its intellectual property which is subject to a negative pledge, and certain other customary exclusions.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">At the Company&#8217;s option, it may prepay the outstanding principal balance of any term loans in whole but not in part, subject to a prepayment fee of: (a) 3.0% of the term loans then extended to the Company if the prepayment occurs on or prior to August 28, 2021, (b) 2.0% of the term loans then extended to the Company if the prepayment occurs after August 28, 2021 but on or prior to August 28, 2022, or (c) 1.0% of the term loans then extended to the Company if the prepayment occurs after August 28, 2022 but before November 1, 2024. The Amended Credit Facility includes customary affirmative and restrictive covenants applicable to the Company. Affirmative covenants include, among others, covenants requiring the Company to maintain its corporate existence and governmental approvals, deliver certain financial reports, maintain insurance coverage and satisfy certain requirements regarding </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">deposit accounts. The Amendment removed the requirement for the Company to maintain a minimum liquidity ratio. The restrictive covenants include, among others, requirements relating to the Company&#8217;s ability to transfer collateral, incur additional indebtedness, engage in mergers or acquisitions, pay dividends or make other distributions, make investments, create liens, sell assets and agree to a change in control, in each case subject to certain customary exceptions.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company&#8217;s payment obligations under the Amended Credit Facility are subject to acceleration upon the occurrence of specified events of default, which include, but are not limited to, the occurrence of a material adverse change in the Company&#8217;s business, operations, or financial or other condition. Amounts outstanding upon the occurrence of an event of default are payable upon SVB&#8217;s demand and shall accrue interest at an additional rate of 5.0% per annum of the past due amount outstanding. As of September&#160;30, 2020, the Company was in compliance with all covenants under the Amended Credit Facility. As such, as of September&#160;30, 2020, the classification of the loan balance as stated on the balance sheet was based on the timing of defined future payment obligations.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The unamortized issuance costs under the Existing Credit Facility were $139 as of the date of the Amendment. The Company incurred debt issuance costs paid to the lender in connection with the Amended Credit Facility of $17. The Company recorded such costs, including the settlement of the final payment obligation under the Existing Credit Facility as a discount from the carrying value of the term loans which are amortized as interest expense using the effective-interest method over the term of the Amended Credit Facility. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, there was $5,200 in term loans outstanding under the Amended Credit Facility and the debt consisted of the following:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:84.957%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total debt</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,200&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Debt financing costs, net of accretion</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(262)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accretion related to final payment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Long-term debt, net</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,944&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, the estimated future principal payments due are as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:84.957%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2021</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,213&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,080&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,907&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total debt</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,200&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div>During the three months ended September&#160;30, 2020 and 2019, and the nine months ended September&#160;30, 2020 and 2019, the Company recognized $60, $51, $173 and $64, respectively, of interest expense related to the Existing Credit Facility and Amended Credit Facility, as applicable.<span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -URI http://asc.fasb.org/topic&amp;trid=2208564<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140218018117672">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stockholders' equity<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquityNoteAbstract', window );"><strong>Stockholders' Equity Note [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockholdersEquityNoteDisclosureTextBlock', window );">Stockholders&#8217; equity</a></td>
<td class="text">Stockholders&#8217; equity <div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Preferred stock</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, the Company had 25,000,000 shares of authorized preferred stock. No shares of preferred stock have been issued.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">At-the-market equity offering program</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In July 2018, the Company established an at-the-market (ATM) equity offering program (the 2018 ATM) pursuant to which it offered and sold up to $75,000 of its common stock from time to time at prevailing market prices. In April 2020, the Company sold 8,938,599 and 1,962,000 shares of common stock at $5.59 per share and $7.74 per share, respectively, to raise aggregate gross proceeds of $65,153 through the 2018 ATM facility. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $62,976. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In May 2020, the Company terminated the 2018 ATM and established a new ATM equity offering program (the 2020 ATM) pursuant to which it is able to sell up to $100,000 of its common stock from time to time at prevailing market prices. As of September&#160;30, 2020, the Company had not sold any shares under the 2020 ATM.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Follow-on offering</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2020, the Company sold 9,200,000 shares of common stock, in an underwritten public offering price to the public of $19.00 per share, resulting in gross proceeds of approximately $174,800. Net proceeds to the Company after deducting fees, commissions and other expenses related to the offering were approximately $163,991.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Warrants</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In connection with a 2013 Series&#160;A-1 Preferred Stock issuance, the Company granted to certain investors warrants to purchase 129,491 shares of common stock. The warrants have a $0.05 per share exercise price and a contractual life of 10 years. The fair value of these warrants was recorded as a component of equity at the time of issuance. As of September&#160;30, 2020, there were warrants to purchase 39,474 shares of common stock.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Exchange warrants</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On November 26, 2019, the Company entered into an exchange agreement with entities affiliated with Biotechnology Value Fund, L.P. (the Exchanging Stockholders), pursuant to which the Exchanging Stockholders exchanged an aggregate of 2,575,000 shares of common stock for warrants (the Exchange Warrants) to purchase an aggregate of 2,575,000 shares of common stock (subject to adjustment in the event of any stock dividends and splits, reverse stock split, merger or consolidation, change of control, reorganization or similar transaction, as described in the Exchange Warrants), with an exercise price of $0.0001 per share.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On March 2, 2020, the Exchanging Stockholders exercised the Exchange Warrants in full on a net cashless exercise basis, resulting in the issuance of 2,574,971 shares of common stock.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Common stock</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The holders of the common stock are entitled to one vote for each share held. Common stockholders are not entitled to receive dividends, unless declared by the Board of Directors (the Board).</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">At September&#160;30, 2020 and December&#160;31, 2019, there were 6,995,704 and 7,782,582, respectively, shares of common stock reserved for the exercise of outstanding stock options, restricted stock units and warrants, as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,215,368&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,720,772&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted stock units</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">740,862&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">447,336&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Warrants</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exchange warrants</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,575,000&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,995,704&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7,782,582&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.</p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982439304">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract', window );"><strong>Share-based Payment Arrangement [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock', window );">Stock options</a></td>
<td class="text">Stock options<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Stock option plans</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2017, the Company&#8217;s stockholders approved the 2017 Stock Incentive Plan (the 2017 Plan). Under the 2017 Plan, up to 2,255,000 shares of common stock were initially available to be granted to the Company's employees, officers, directors, consultants and advisors in the form of options, restricted stock units (RSUs) or other stock-based awards. The number of shares of common stock issuable under the 2017 Plan will be cumulatively increased annually by 4% of the outstanding shares or such lesser amount specified by the Board. The terms of the awards are determined by the Board, subject to the provisions of the 2017 Plan. Any cancellations under the 2007 Plan, which expired in June 2017, would increase the number of shares that could be granted under the 2017 Plan. In January 2020, the number of shares of common stock issuable under the 2017 Plan was increased by 1,815,520 shares. As of September&#160;30, 2020, there were 1,320,916 shares available for future issuance under the 2017 Plan. During the nine months ended September 30, 2020, the Company granted 2,165,306 RSUs and options to purchase shares of common stock to employees under the 2017 Plan. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Inducement awards</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On September 2, 2020, the Company granted its senior vice president of regulatory affairs an option to purchase up to 120,000 shares of common stock as an inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4). No underwriters were involved in this issuance of securities. The securities were issued pursuant to Section 4(a)(2) under the Securities Act of 1933, as amended, relating to transactions by an issuer not involving any public offering. These options are subject to terms substantially the same as the 2017 Plan.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">With respect to the stock option grants as described above, the exercise price per share will equal the fair market value of the common stock on the date of grant, and the vesting period is generally four years. Nonqualified stock options will be granted at an exercise price established by the Board at its sole discretion (which has not been less than fair market value on the date of grant) and the vesting periods may vary. Options granted as described above expire no later than 10 years from the date of grant. The Board may accelerate vesting or extend the expiration of granted options in the case of a merger, consolidation, dissolution, or liquidation of the Company.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Stock option activity</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A summary of the options activity under the Plans is as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Number<br/>of&#160;Shares</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Weighted-<br/>Average<br/>Exercise&#160;Price</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Outstanding at January&#160;1, 2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,720,772&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5.24&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Granted</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,960,374&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">9.41&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exercised</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(338,069)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5.13&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cancelled</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(127,709)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7.70&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Outstanding at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,215,368&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.52&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exercisable at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,256,514&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4.87&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The weighted-average grant date fair value of options granted during the nine months ended September&#160;30, 2020 and 2019, was $6.17 and $2.47 per share, respectively.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Cash received from the exercise of stock options was $1,732 and $121 for the nine months ended September&#160;30, 2020 and 2019, respectively.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Restricted stock units (RSUs)</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In July 2019, the Company issued RSUs with service conditions to employees. The awards cliff-vest two years after the grant date. In January 2020, the Company issued 324,932 RSUs with a service condition to employees for which the vesting term is annually over four years. Vesting of these awards is contingent on the fulfillment of the service conditions during the vesting term.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A summary of the RSU activity under the 2017 Plan is as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:97.275%"><tr><td style="width:1.0%"/><td style="width:84.567%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:13.233%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Number of Shares</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested at January&#160;1, 2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">447,336&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Granted</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">324,932&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Vested</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Forfeited</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(31,406)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">740,862&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Stock-based compensation expense</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company uses the provisions of ASC 718, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Stock Compensation</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, to account for all stock-based awards to employees and non-employees.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The measurement date for employee awards is generally the date of grant. Stock-based compensation expense is recognized over the requisite service period, which is generally the vesting period, using the straight-line method.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents stock-based compensation expense by award type included within the Company&#8217;s condensed consolidated statement of operations and comprehensive loss:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,520&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,055&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,025&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,240&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted stock units</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">335&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">184&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">962&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">184&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Employee stock purchase plan</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">63&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">46&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">196&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">186&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock-based compensation expense included in Total operating expenses</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,918&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,285&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,183&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,610&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents stock-based compensation expense as reflected in the Company&#8217;s condensed consolidated statements of operations and comprehensive loss:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Research and development</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">952&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">587&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,554&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,636&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">General and administrative</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">966&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">698&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,629&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,974&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock-based compensation expense included in Total operating expenses</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,918&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,285&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,183&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,610&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, there was $15,007 and $2,269 of unrecognized stock compensation expense related to unvested stock options and unvested RSUs, respectively, that is expected to be recognized over a weighted-average period of 2.5 years and 2.6 years, respectively.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Risk-free interest rate</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">0.4&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1.9&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1.3&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2.4&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected dividend yield</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected term (years)</span></td><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.10</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.11</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.04</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5.99</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected stock price volatility</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">81&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">75&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">72&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">74&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Employee Stock Purchase Plan</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the year ended December 31, 2017, the Board adopted, and the Company&#8217;s stockholders approved the 2017 employee stock purchase plan (the 2017 ESPP). The Company initially reserved 225,000 shares of common stock for issuance under the 2017 ESPP. In January 2020, the number of shares of common stock for issuance under the 2017 ESPP was increased by 450,000 shares. For the nine months ended September&#160;30, 2020 and 2019, the Company issued 68,419 and 82,281, respectively, shares under the 2017 ESPP. The Company did not issue any shares under the 2017 ESPP for the three months ended September&#160;30, 2020 and 2019. As of September&#160;30, 2020, there were 656,666 shares available for issuance under the 2017 ESPP.</span></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -URI http://asc.fasb.org/topic&amp;trid=2228938<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982503064">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Leases<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LeasesAbstract', window );"><strong>Leases [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeasesTextBlock', window );">Leases</a></td>
<td class="text">Leases<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company has an operating lease for its office space in Cambridge, MA and operating and finance leases for certain equipment. In March 2020, the Company entered into the Seventh Amendment to the office space lease to extend the term of the lease through March 2026 and to provide the Company with a tenant improvement allowance of $172. The current rate per square foot that is in place through March 2021 (the original expiration date of the lease) did not change. After March 2021, there are predetermined fixed escalations of the rate as outlined in the amendment. The Company has an option to extend the lease term for an additional five years. The Company&#8217;s exercise of this option was not considered reasonably certain as of September&#160;30, 2020. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The extension is accounted for as a lease modification. The Company assessed the lease classification of the amended office space lease at the modification date and determined that the amended office space lease should be accounted for as an operating lease. The right-of-use asset and corresponding operating lease liability have been remeasured based on the present value of remaining lease payments over the remaining extended lease term, using the incremental borrowing rate applicable as of the lease modification date. The Company determined the appropriate incremental borrowing rate by using a synthetic credit rating which was estimated based on an analysis of outstanding debt of companies with similar credit and financial profiles. Since the operating lease is a net lease, as the non-lease components (i.e., common area maintenance) are paid separately from rent based on actual costs incurred, such non-lease components were not included in the right-of-use asset and liability and are reflected as an expense in the period incurred. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As a result of the modification in March 2020, the Company recorded an increase of $9,980 to its right-of-use (ROU) asset and lease liabilities in the first quarter of 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Operating leases</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Finance leases</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">604&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">29&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2021</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,772&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">116&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,843&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">84&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,928&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">74&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024 and thereafter</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,904&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">18&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total lease payments</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,051&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value adjustment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(4,165)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(30)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value of lease liabilities</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,886&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">291&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeFinanceLeasesTextBlock', window );">Leases</a></td>
<td class="text">Leases<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company has an operating lease for its office space in Cambridge, MA and operating and finance leases for certain equipment. In March 2020, the Company entered into the Seventh Amendment to the office space lease to extend the term of the lease through March 2026 and to provide the Company with a tenant improvement allowance of $172. The current rate per square foot that is in place through March 2021 (the original expiration date of the lease) did not change. After March 2021, there are predetermined fixed escalations of the rate as outlined in the amendment. The Company has an option to extend the lease term for an additional five years. The Company&#8217;s exercise of this option was not considered reasonably certain as of September&#160;30, 2020. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The extension is accounted for as a lease modification. The Company assessed the lease classification of the amended office space lease at the modification date and determined that the amended office space lease should be accounted for as an operating lease. The right-of-use asset and corresponding operating lease liability have been remeasured based on the present value of remaining lease payments over the remaining extended lease term, using the incremental borrowing rate applicable as of the lease modification date. The Company determined the appropriate incremental borrowing rate by using a synthetic credit rating which was estimated based on an analysis of outstanding debt of companies with similar credit and financial profiles. Since the operating lease is a net lease, as the non-lease components (i.e., common area maintenance) are paid separately from rent based on actual costs incurred, such non-lease components were not included in the right-of-use asset and liability and are reflected as an expense in the period incurred. </span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As a result of the modification in March 2020, the Company recorded an increase of $9,980 to its right-of-use (ROU) asset and lease liabilities in the first quarter of 2020.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Operating leases</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Finance leases</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">604&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">29&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2021</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,772&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">116&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,843&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">84&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,928&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">74&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024 and thereafter</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,904&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">18&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total lease payments</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,051&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value adjustment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(4,165)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(30)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value of lease liabilities</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,886&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">291&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for finance leases of lessee. Includes, but is not limited to, description of lessee's finance lease and maturity analysis of finance lease liability.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -URI http://asc.fasb.org/subtopic&amp;trid=77888251<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for operating leases of lessee. Includes, but is not limited to, description of operating lease and maturity analysis of operating lease liability.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -URI http://asc.fasb.org/subtopic&amp;trid=77888251<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982506248">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Commitments<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommitmentsAndContingenciesDisclosureAbstract', window );"><strong>Commitments and Contingencies Disclosure [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommitmentsDisclosureTextBlock', window );">Commitments</a></td>
<td class="text">CommitmentsLicense agreementsThrough September&#160;30, 2020, the Company had licensed intellectual property from three biotechnology companies. The consideration included upfront payments and a commitment to pay annual license fees, milestone payments and, upon product commercialization, royalties on revenue generated from the sale of products covered by the licenses. The Company recorded a $750 milestone payment for the dosing of the first patient in the XMT-1592 trial during the nine months ended September&#160;30, 2020. The Company recorded a milestone payment of $600 during the three and nine months ended September&#160;30, 2019 upon the dosing of the first patient in the expansion cohort of the XMT-1536 clinical trial. The Company did not record any milestone payments during the three months ended September 30, 2020.<span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The entire disclosure for significant arrangements with third parties, which includes operating lease arrangements and arrangements in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services, and operating lease arrangements. Descriptions may include identification of the specific goods and services, period of time covered, minimum quantities and amounts, and cancellation rights.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 440<br> -URI http://asc.fasb.org/topic&amp;trid=2144648<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983861720">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Summary of Significant Accounting Policies (Policies)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccountingPoliciesAbstract', window );"><strong>Accounting Policies [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ConsolidationPolicyTextBlock', window );">Principles of Consolidation</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Principles of Consolidation</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The accompanying unaudited condensed consolidated financial statements include those of the Company and its wholly owned subsidiary, Mersana Securities Corp. All intercompany balances and transactions have been eliminated.</span></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_UseOfEstimates', window );">Use of Estimates</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of the Company&#8217;s unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company&#8217;s management evaluates its estimates which include, but are not limited to, management&#8217;s judgments with respect to the identification of performance obligations and standalone selling prices of those performance obligations within its revenue arrangements, accrued expenses, valuation of stock-based awards and income taxes. Actual results could differ from those estimates.</span></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SegmentReportingPolicyPolicyTextBlock', window );">Segment Information</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Segment Information</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker, or decision making group, in deciding how to allocate resources and assess performance. The Company views its operations and manages its business as a single operating segment, which is the business of discovering and developing ADCs.</span></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueMeasurementPolicyPolicyTextBlock', window );">Fair Value Measurements</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Fair Value Measurements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. ASC Topic&#160;820&#160;</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Fair Value Measurement</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">&#160;(ASC&#160;820) establishes a three-level valuation hierarchy for instruments measured at fair value. The hierarchy is based on the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows:</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Level&#160;1&#8212;Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Level&#160;2&#8212;Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Level&#160;3&#8212;Inputs to the valuation methodology are unobservable and significant to the fair value measurement.</span></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashAndCashEquivalentsPolicyTextBlock', window );">Cash and Cash Equivalents</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Cash and Cash Equivalents</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company considers all highly liquid investments with an original maturity, or a remaining maturity at the time of purchase, of three months or less to be cash equivalents. The Company invests excess cash primarily in money market funds, commercial paper and government agency securities, which are highly liquid and have strong credit ratings. These investments are subject to minimal credit and market risks. Cash and cash equivalents are stated at cost, which approximates market value.</span></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_MarketableSecuritiesPolicy', window );">Marketable Securities</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Marketable Securities</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Short-term marketable securities consist of investments in debt securities with maturities greater than three months and less than one year from the balance sheet date. The Company classifies all of its marketable securities as available-for-sale. Accordingly, these investments are recorded at fair value. Amortization and accretion of discounts and premiums are recorded as interest income within other income. Prior to the adoption of ASU 2016-13,</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%"> Financial Instruments - Credit Losses</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, unrealized gains and losses on available-for-sale securities are included in other accumulated comprehensive income (loss) as a component of stockholders&#8217; equity until realized. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other income (expense), net, based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers various factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. Fair value is determined based on quoted market prices.</span></div><span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashAndCashEquivalentsRestrictedCashAndCashEquivalentsPolicy', window );">Other Assets</a></td>
<td class="text">Other AssetsThe Company recorded other assets of $2,153 and $1,453 as of September&#160;30, 2020 and December&#160;31, 2019, respectively, comprised of $1,832 and $1,132, respectively, held by a service provider, and restricted cash of $321 at the end of each period held as security deposits for a standby letter of credit related to a facility lease.<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EarningsPerSharePolicyTextBlock', window );">Net Loss per Share</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Net Loss per Share</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without further consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury stock and if-converted methods.</span></div>For purposes of the diluted net loss per share calculation, stock options, unvested restricted stock units (RSUs), warrants to purchase common stock and options to purchase common stock are considered to be potentially dilutive securities, but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented.<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock', window );">Recently Issued Accounting Pronouncements</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Recently Issued Accounting Pronouncements</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In November 2018, the FASB issued ASU No. 2018-18, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">. The main provisions of ASU 2018-18 include: (i) clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue when the collaborative arrangement participant is a customer in the context of a unit of account and (ii) precluding the presentation of transactions with collaborative arrangement participants that are not directly related to sales to third parties together with revenue. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The guidance per ASU 2018-18 is to be adopted retrospectively to the date of initial application of Topic 606. The Company adopted the new standard effective January 1, 2020. The adoption of this standard did not have a material impact on the Company&#8217;s consolidated financial statements and related disclosures.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In June 2016, the FASB issued ASU 2016-13, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%">Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">, which requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. Historically, U.S. GAAP delayed recognition of the full amount of credit losses until the loss was probable of occurring. Under this ASU, the income statement will reflect an entity&#8217;s current estimate of all expected credit losses. The measurement of expected credit losses will be based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses rather than as a direct write-down of the security. This ASU is effective for annual periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption is permitted. The Company adopted the new standard effective January 1, 2020 using the modified retrospective method. The adoption of this standard did not have a material impact on the Company&#8217;s consolidated financial statements and related disclosures.</span></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=d3e4273-108586<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(1))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=84158767&amp;loc=d3e18780-107790<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Entity's cash and cash equivalents accounting policy with respect to restricted balances.  Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(1)(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(1))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=84158767&amp;loc=d3e18780-107790<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=d3e4273-108586<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting.  The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy for fair value measurements of financial and non-financial assets, liabilities and instruments classified in shareholders' equity. Disclosures include, but are not limited to, how an entity that manages a group of financial assets and liabilities on the basis of its net exposure measures the fair value of those assets and liabilities.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy for investment classified as marketable security.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 320<br> -Section 50<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=120252992&amp;loc=d3e62652-112803<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy pertaining to new accounting pronouncements that may impact the entity's financial reporting. Includes, but is not limited to, quantification of the expected or actual impact.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy for segment reporting.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 29<br> -Subparagraph (e)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8864-108599<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=84158767&amp;loc=d3e18780-107790<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 29<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8864-108599<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 41<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9038-108599<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 29<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8864-108599<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 29<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8864-108599<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 29<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8864-108599<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 29<br> -Subparagraph (d)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8864-108599<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SegmentReportingPolicyPolicyTextBlock</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.</p></div>
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<tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983402360">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Summary of Significant Accounting Policies (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccountingPoliciesAbstract', window );"><strong>Accounting Policies [Abstract]</strong></a></td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock', window );">Schedule of Cash and Cash Equivalents</a></td>
<td class="text"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30, 2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30, 2019</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning<br/>of period</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">End<br/>of period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning<br/>of period</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">End<br/>of period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash and cash equivalents</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">62,351&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">270,936&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">59,634&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">58,196&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted cash included in other assets, noncurrent</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">371&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total cash, cash equivalents and restricted cash per statement of cash flows</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">62,672&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">271,257&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">60,005&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">58,517&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table><span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock', window );">Schedule of Restricted Cash and Cash Equivalents</a></td>
<td class="text"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30, 2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30, 2019</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning<br/>of period</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">End<br/>of period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning<br/>of period</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">End<br/>of period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cash and cash equivalents</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">62,351&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">270,936&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">59,634&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">58,196&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted cash included in other assets, noncurrent</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">371&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total cash, cash equivalents and restricted cash per statement of cash flows</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">62,672&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">271,257&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">60,005&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">58,517&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table><span></span>
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<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock', window );">Schedule of outstanding potentially dilutive securities excluded from calculation of diluted net loss per share</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table sets forth the outstanding potentially dilutive securities that have been excluded from the calculation of diluted net loss per share for the three and nine months ended September&#160;30, 2020 and 2019, because to include them would be anti-dilutive (in common stock equivalent shares):</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%"> </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:49.541%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:23.258%"/><td style="width:0.1%"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td style="width:0.1%"/><td style="width:0.441%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:23.260%"/><td style="width:0.1%"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three and Nine Months Ended<br/>September 30, 2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three and Nine Months Ended<br/>September 30, 2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,215,368&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,718,597&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested restricted stock units</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">740,862&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">447,336&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Warrants</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,995,704&#160;</span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,205,407&#160;</span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr></table></div><span></span>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980860872">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration Agreements (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationAgreementsAbstract', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents changes in the balances of our contract assets and liabilities during the nine months ended September&#160;30, 2020 and 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>Beginning<br/>of Period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Additions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Deductions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>End of Period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Nine months ended September 30, 2020</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract assets</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract liabilities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,815&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">817&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,998&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span><br/></span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>Beginning<br/>of Period</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Additions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Deductions</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Balance at<br/>End of Period</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Nine months ended September 30, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract assets</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Contract liabilities:</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 12pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Deferred revenue</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">46,196&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">41,550&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,646&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">During the three and nine months ended September&#160;30, 2020 and 2019, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">Revenue recognized in the period from:</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Amounts included in the contract liability at the beginning of the period</span></td><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">834&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">817&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">41,550&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Performance obligations satisfied in previous periods</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span 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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of receivable, contract asset, and contract liability from contract with customer. Includes, but is not limited to, change in contract asset and contract liability.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 10<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130551-203045<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986803416">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Fair value measurements (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueDisclosuresAbstract', window );"><strong>Fair Value Disclosures [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTableTextBlock', window );">Schedule of assets and liabilities measured and carried at fair value</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents information about the Company's assets and liabilities regularly measured and carried at a fair value and indicates the level within fair value hierarchy of the valuation techniques utilized to determine such value as of December&#160;31, 2019. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company had no marketable securities as of </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2020</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">: </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Fair<br/>Value</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Quoted&#160;Prices<br/>in&#160;Active<br/>Markets<br/>(Level&#160;1)</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Significant<br/>Other<br/>Observable<br/>Inputs<br/>(Level&#160;2)</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Significant<br/>Unobservable<br/>Inputs<br/>(Level&#160;3)</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Marketable securities:</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Commercial paper</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Corporate bonds</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">12,010&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">12,010&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">U.S. Treasuries</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,439&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">23,950&#160;</span></td><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="padding:0 1pt"/><td style="border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="border-bottom:3pt 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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.</p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982635624">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Marketable securities (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_MarketableSecuritiesAbstract', window );"><strong>Marketable Securities [Abstract]</strong></a></td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock', window );">Schedule of reconciliation of marketable securities from cost basis to fair value</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table summarizes marketable securities held at December&#160;31, 2019. </span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company had no marketable securities as of </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">September&#160;30, 2020</span><span style="background-color:#ffffff;color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">: </span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.839%"><tr><td style="width:1.0%"/><td style="width:45.127%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.741%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.602%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.744%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Amortized<br/>Cost</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Gross<br/>Unrealized<br/>Gains</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Gross<br/>Unrealized<br/>Losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Fair<br/>Value</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">December 31, 2019</span></td><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Commercial paper</span></td><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,940&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Corporate bonds</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,990&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">20&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">12,010&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">U.S. Treasuries</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,484&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">13,489&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,414&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">25&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">37,439&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982445192">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Accrued expenses (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccruedLiabilitiesCurrentAbstract', window );"><strong>Accrued Liabilities, Current [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock', window );">Schedule of accrued expenses</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Accrued expenses consisted of the following as of September&#160;30, 2020 and December&#160;31, 2019:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued payroll and related expenses</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,647&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,037&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued preclinical, manufacturing and clinical expenses</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,600&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,230&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued professional fees and insurance</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">861&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">675&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accrued other</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">65&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">44&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,173&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">8,986&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccruedLiabilitiesCurrentAbstract</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of the (a) carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business (accounts payable); (b) other payables; and (c) accrued liabilities. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). An alternative caption includes accrued expenses.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock</td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982345336">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Debt (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtDisclosureAbstract', window );"><strong>Debt Disclosure [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfDebtTableTextBlock', window );">Schedule of debt</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, there was $5,200 in term loans outstanding under the Amended Credit Facility and the debt consisted of the following:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:84.957%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total debt</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,200&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="display:none"/><td colspan="3" style="display:none"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Debt financing costs, net of accretion</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(262)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Accretion related to final payment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Long-term debt, net</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,944&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock', window );">Schedule of estimated future payments</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As of September&#160;30, 2020, the estimated future principal payments due are as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:84.957%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2021</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,213&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,080&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,907&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total debt</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,200&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of information pertaining to short-term and long-debt instruments or arrangements, including but not limited to identification of terms, features, collateral requirements and other information necessary to a fair presentation.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of maturity and sinking fund requirement for long-term debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6802200&amp;loc=d3e1835-112601<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982513736">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stockholders' equity (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfStockByClassTextBlock', window );">Schedule for number of common stock reserved for exercise of outstanding stock options and warrants</a></td>
<td class="text"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">September 30,<br/>2020</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">December 31,<br/>2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,215,368&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,720,772&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted stock units</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">740,862&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">447,336&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Warrants</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">39,474&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exchange warrants</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,575,000&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,995,704&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7,782,582&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table><span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information.  Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.</p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980775608">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract', window );"><strong>Share-based Payment Arrangement [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock', window );">Schedule of stock option activity under Plan</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A summary of the options activity under the Plans is as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Number<br/>of&#160;Shares</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Weighted-<br/>Average<br/>Exercise&#160;Price</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Outstanding at January&#160;1, 2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,720,772&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5.24&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Granted</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,960,374&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">9.41&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exercised</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(338,069)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5.13&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Cancelled</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(127,709)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">7.70&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Outstanding at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,215,368&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.52&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Exercisable at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,256,514&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:3pt double #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4.87&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock', window );">Schedule of restricted stock activity</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">A summary of the RSU activity under the 2017 Plan is as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:97.275%"><tr><td style="width:1.0%"/><td style="width:84.567%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:13.233%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Number of Shares</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested at January&#160;1, 2020</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">447,336&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Granted</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">324,932&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Vested</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Forfeited</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(31,406)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Unvested at September&#160;30,&#160;2020</span></td><td colspan="2" style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">740,862&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock', window );">Schedule of stock-based compensation expense by award type</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents stock-based compensation expense by award type included within the Company&#8217;s condensed consolidated statement of operations and comprehensive loss:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock options</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,520&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,055&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">4,025&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,240&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Restricted stock units</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">335&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">184&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">962&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">184&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Employee stock purchase plan</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">63&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">46&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">196&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">186&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock-based compensation expense included in Total operating expenses</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,918&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,285&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,183&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,610&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock', window );">Schedule of stock-based compensation expense as reflected in the Company&#8217;s condensed consolidated statements of operations and comprehensive loss</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table presents stock-based compensation expense as reflected in the Company&#8217;s condensed consolidated statements of operations and comprehensive loss:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Research and development</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">952&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">587&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,554&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,636&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">General and administrative</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">966&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">698&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,629&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,974&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Stock-based compensation expense included in Total operating expenses</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,918&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1,285&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5,183&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">3,610&#160;</span></td><td style="background-color:#cceeff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock', window );">Schedule of weighted average assumptions for estimating fair value of option awards</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:45.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.720%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:11.723%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended<br/>September 30,</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended<br/>September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Risk-free interest rate</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">0.4&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1.9&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">1.3&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2.4&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected dividend yield</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">&#8212;&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected term (years)</span></td><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.10</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.11</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6.04</span></td><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">5.99</span></td></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Expected stock price volatility</span></td><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">81&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">75&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">72&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">74&#160;</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">%</span></td></tr></table></div><span></span>
</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of cost recognized for award under share-based payment arrangement by plan. Includes, but is not limited to, related tax benefit.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (h)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of allocation of amount expensed and capitalized for award under share-based payment arrangement to statement of income or comprehensive income and statement of financial position. Includes, but is not limited to, corresponding line item in financial statement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (h)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 14.F)<br> -URI http://asc.fasb.org/extlink&amp;oid=115993241&amp;loc=d3e301413-122809<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5047-113901<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure for stock option plans. Includes, but is not limited to, outstanding awards at beginning and end of year, grants, exercises, forfeitures, and weighted-average grant date fair value.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (f)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982416664">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Leases (Tables)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LeasesAbstract', window );"><strong>Leases [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock', window );">Schedule of future minimum payments under operating leases</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Operating leases</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Finance leases</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">604&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">29&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2021</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,772&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">116&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,843&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">84&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,928&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">74&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024 and thereafter</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,904&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">18&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total lease payments</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,051&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value adjustment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(4,165)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(30)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value of lease liabilities</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">11,886&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">291&#160;</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><span></span>
</td>
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<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityMaturityTableTextBlock', window );">Schedule of future minimum payments under finance leases</a></td>
<td class="text"><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Following the change, the Company's future minimum lease payments under non-cancellable leases as of September&#160;30, 2020 were as follows:</span></div><div style="margin-bottom:12pt"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:100.000%"><tr><td style="width:1.0%"/><td style="width:70.214%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.842%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.601%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:12.843%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Operating leases</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Finance leases</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2020 (excluding the nine months ended September 30, 2020)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">604&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">29&#160;</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2021</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,772&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">116&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2022</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,843&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">84&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2023</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2,928&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">74&#160;</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">2024 and thereafter</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">6,904&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">18&#160;</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total lease payments</span></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">16,051&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">321&#160;</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Present value adjustment</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">(4,165)</span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" 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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of undiscounted cash flows of finance lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to finance lease liability recognized in statement of financial position.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LeasesAbstract</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Tabular disclosure of undiscounted cash flows of lessee's operating lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to operating lease liability recognized in statement of financial position.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986490600">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Nature of business and basis of presentation - Termination of collaborative arrangement - (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="7">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Jun. 30, 2020</div></th>
<th class="th"><div>Mar. 31, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Jun. 30, 2019</div></th>
<th class="th"><div>Mar. 31, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_NetIncomeLoss', window );">Net loss</a></td>
<td class="nump">$ 22,489<span></span>
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<td class="nump">$ 19,786<span></span>
</td>
<td class="nump">$ 16,926<span></span>
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<td class="nump">$ 16,246<span></span>
</td>
<td class="nump">$ 16,792<span></span>
</td>
<td class="nump">$ 17,071<span></span>
</td>
<td class="num">$ (21,901)<span></span>
</td>
<td class="nump">$ 59,203<span></span>
</td>
<td class="nump">$ 11,962<span></span>
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<tr class="re">
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<td class="nump">$ 11<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="nump">$ 834<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="nump">$ 817<span></span>
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<td class="nump">$ 41,550<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_ResearchCollaborationAndCommercialLicenseAgreementTakeda2016RestatedAgreementAndDevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember', window );">2016 Restated Tokeda Agreement and XMT-1522 Agreement</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
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<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
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<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiabilityRevenueRecognized', window );">Deferred revenue recognized</a></td>
<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="nump">$ 39,965<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217979062456">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Nature of business and basis of presentation - Liquidity (Details) - USD ($)<br> $ in Thousands</strong></div></th>
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<th class="th" colspan="1"></th>
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<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
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<td class="text">false<span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The cumulative amount of the reporting entity's undistributed earnings or deficit.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(30)(a)(3))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 65<br> -Paragraph 15<br> -Subparagraph (g)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121322162&amp;loc=SL121327923-165333<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(23)(a)(4))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 40<br> -Section 65<br> -Paragraph 2<br> -Subparagraph (h)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=121370832&amp;loc=SL117420844-207641<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 40<br> -Section 65<br> -Paragraph 2<br> -Subparagraph (g)(2)(i)<br> -URI http://asc.fasb.org/extlink&amp;oid=121370832&amp;loc=SL117420844-207641<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicates (true false) whether there was substantial doubt about ability to continue as going concern within one year after date financial statements are issued.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 205<br> -SubTopic 40<br> -Section 50<br> -Paragraph 13<br> -URI http://asc.fasb.org/extlink&amp;oid=116846462&amp;loc=SL51888449-203568<br></p></div>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986546584">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Nature of business and basis of presentation - Sale of Stock (Details) - USD ($)<br> $ in Thousands</strong></div></th>
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<tr>
<th class="th"><div>Jun. 30, 2020</div></th>
<th class="th"><div>Apr. 30, 2020</div></th>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<tr class="ro">
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsequentEventLineItems', window );"><strong>Subsequent Event [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
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</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Issuance of common stock under public offering, net of issuance costs (in shares)</a></td>
<td class="nump">9,200,000<span></span>
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<td class="text">&#160;<span></span>
</td>
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<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts', window );">Proceeds from stock issuance, net of issuance costs</a></td>
<td class="nump">$ 163,991<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts">
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The net proceeds from the additional capital contribution to the entity after deducting fees, commissions and other expenses.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts</td>
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<td><strong> Balance Type:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of new stock issued during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<td><strong> Name:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2018ATMMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
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<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember</td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983523272">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Summary of significant accounting policies - Cash and Cash Equivalents (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Dec. 31, 2018</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract', window );"><strong>Cash, cash equivalents and restricted cash</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashAndCashEquivalentsAtCarryingValue', window );">Cash and cash equivalents</a></td>
<td class="nump">$ 270,936<span></span>
</td>
<td class="nump">$ 62,351<span></span>
</td>
<td class="nump">$ 58,196<span></span>
</td>
<td class="nump">$ 59,634<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RestrictedCashNoncurrent', window );">Restricted cash included in other assets</a></td>
<td class="nump">321<span></span>
</td>
<td class="nump">321<span></span>
</td>
<td class="nump">321<span></span>
</td>
<td class="nump">371<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents', window );">Total cash, cash equivalents and restricted cash per statement of cash flows</a></td>
<td class="nump">$ 271,257<span></span>
</td>
<td class="nump">$ 62,672<span></span>
</td>
<td class="nump">$ 58,517<span></span>
</td>
<td class="nump">$ 60,005<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RestrictedCashAssetStatementOfFinancialPositionExtensibleList', window );">Restricted cash, Balance Sheet Location</a></td>
<td class="text">us-gaap:OtherAssetsNoncurrent<span></span>
</td>
<td class="text">us-gaap:OtherAssetsNoncurrent<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 4<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3044-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6676-107765<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CashAndCashEquivalentsAtCarryingValue</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 24<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3521-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 4<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3044-108585<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=SL98516268-108586<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsAbstract</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicates line item in statement of financial position that includes cash restricted to withdrawal or usage.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=SL98516268-108586<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<td style="white-space:nowrap;">us-gaap_RestrictedCashAssetStatementOfFinancialPositionExtensibleList</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash restricted as to withdrawal or usage, classified as noncurrent. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 4<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6812-107765<br><br>Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(17))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=121583591&amp;loc=SL98516268-108586<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 954<br> -SubTopic 210<br> -Section 45<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=120413173&amp;loc=SL116631458-115580<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RestrictedCashNoncurrent</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<DOCUMENT>
<TYPE>XML
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<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217978656920">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Summary of significant accounting policies - Other Assets (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RestrictedCashAndInvestmentsAbstract', window );"><strong>Other Assets</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherAssetsNoncurrent', window );">Other assets</a></td>
<td class="nump">$ 2,153<span></span>
</td>
<td class="nump">$ 1,453<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SecurityDeposit', window );">Security deposit</a></td>
<td class="nump">321<span></span>
</td>
<td class="nump">321<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RetainageDeposit', window );">Held by service provider</a></td>
<td class="nump">$ 1,832<span></span>
</td>
<td class="nump">$ 1,132<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherAssetsNoncurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of noncurrent assets classified as other.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherAssetsNoncurrent</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>debit</td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RestrictedCashAndInvestmentsAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RestrictedCashAndInvestmentsAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RetainageDeposit">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The amount of assets, typically cash, provided to suppliers of goods in advance of receipt and acceptance, or services (such as research facilities, lawyers or consultants), which is held by such parties until the entity either effects full payment (including applying the retainer) or obtains release from liability.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.8,17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RetainageDeposit</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SecurityDeposit">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.8,17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SecurityDeposit</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>44
<FILENAME>R34.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217987225256">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Summary of significant accounting policies - Antidilutive securities (Details) - shares<br></strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems', window );"><strong>Anti-dilutive securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount', window );">Anti-dilutive securities (in shares)</a></td>
<td class="nump">6,995,704<span></span>
</td>
<td class="nump">5,205,407<span></span>
</td>
<td class="nump">6,995,704<span></span>
</td>
<td class="nump">5,205,407<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_WarrantMember', window );">Warrants</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems', window );"><strong>Anti-dilutive securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount', window );">Anti-dilutive securities (in shares)</a></td>
<td class="nump">39,474<span></span>
</td>
<td class="nump">39,474<span></span>
</td>
<td class="nump">39,474<span></span>
</td>
<td class="nump">39,474<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_RestrictedStockUnitsRSUMember', window );">Restricted stock units</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems', window );"><strong>Anti-dilutive securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount', window );">Anti-dilutive securities (in shares)</a></td>
<td class="nump">740,862<span></span>
</td>
<td class="nump">447,336<span></span>
</td>
<td class="nump">740,862<span></span>
</td>
<td class="nump">447,336<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_EmployeeStockOptionMember', window );">Stock options</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems', window );"><strong>Anti-dilutive securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount', window );">Anti-dilutive securities (in shares)</a></td>
<td class="nump">6,215,368<span></span>
</td>
<td class="nump">4,718,597<span></span>
</td>
<td class="nump">6,215,368<span></span>
</td>
<td class="nump">4,718,597<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 260<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=6371337&amp;loc=d3e3550-109257<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_WarrantMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_WarrantMember</td>
</tr>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
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<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
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</tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_RestrictedStockUnitsRSUMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
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<tr>
<td><strong> Name:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217978630632">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Summary of significant accounting policies - Recently Issued Accounting Pronouncement (Details)<br></strong></div></th>
<th class="th"><div>Jan. 01, 2020</div></th>
</tr>
<tr class="rh">
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<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
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<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
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<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201808Member', window );">Accounting Standards Update 2018-08</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
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<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted', window );">Change in Accounting Principle, Accounting Standards Update, Adopted</a></td>
<td class="text">true<span></span>
</td>
</tr>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicates (true false) whether accounting standards update was adopted.</p></div>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<td><strong> Name:</strong></td>
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<td><strong> Name:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217984330536">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements - Merck KGaA (Details) - Merck KGaA<br> $ in Thousands</strong></div></th>
<th class="th" colspan="1">1 Months Ended</th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
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<tr>
<th class="th">
<div>Jun. 30, 2014 </div>
<div>USD ($) </div>
<div>target</div>
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<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($) </div>
<div>target</div>
</th>
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<div>Dec. 31, 2017 </div>
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<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="nump">$ 12,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
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<td class="nump">6<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense', window );">Amount of additional fees receivable when target is designated and commercial license to target is granted</a></td>
<td class="nump">$ 0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsTargetsDesignatedNumber', window );">Number of targets designated | target</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">6<span></span>
</td>
<td class="nump">6<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsDevelopmentMilestonesPaymentReceivableNextMilestone', window );">Next potential development milestone payment eligible to receive</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 500<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
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<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of additional fees receivable when a target is designated and the commercial license to the target is granted under terms of the agreement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsAdditionalPaymentToObtainDevelopmentAndCommercialLicense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
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<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
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</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationArrangementsDevelopmentMilestonesPaymentReceivableNextMilestone">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of the next potential development milestone the company will be eligible to receive.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsDevelopmentMilestonesPaymentReceivableNextMilestone</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of targets designated as of balance sheet date.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsTargetsDesignatedNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:integerItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborativeArrangementsExclusiveTargetsNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of exclusive targets entity provided right to develop under terms of agreement as of balance sheet date.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborativeArrangementsExclusiveTargetsNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:integerItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborativeArrangementsUpfrontPayment">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of upfront payment received during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborativeArrangementsUpfrontPayment</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementMerckKgaaMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementMerckKgaaMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>47
<FILENAME>R37.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983185016">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements - Merck KGaA - Accounting Analysis (Details)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Sep. 30, 2019 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($) </div>
<div>target</div>
</th>
<th class="th">
<div>Sep. 30, 2019 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Dec. 31, 2019 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Dec. 31, 2018 </div>
<div>USD ($)</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="nump">$ 11<span></span>
</td>
<td class="nump">$ 844<span></span>
</td>
<td class="nump">$ 817<span></span>
</td>
<td class="nump">$ 42,081<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ResearchAndDevelopmentExpense', window );">Research and development</a></td>
<td class="nump">16,546<span></span>
</td>
<td class="nump">13,701<span></span>
</td>
<td class="nump">44,179<span></span>
</td>
<td class="nump">42,610<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiability', window );">Deferred revenue</a></td>
<td class="nump">$ 3,998<span></span>
</td>
<td class="nump">$ 4,646<span></span>
</td>
<td class="nump">3,998<span></span>
</td>
<td class="nump">4,646<span></span>
</td>
<td class="nump">$ 4,815<span></span>
</td>
<td class="nump">$ 46,196<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerProductAndServiceExtensibleList', window );">Type of revenue [Extensible List]</a></td>
<td class="text">mrsn:CollaborationMember<span></span>
</td>
<td class="text">mrsn:CollaborationMember<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementAndSupplyAgreementMerckKgaaMember', window );">Merck KGaA Agreement and Merck KGaA Supply Agreement</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiability', window );">Deferred revenue</a></td>
<td class="nump">$ 3,998<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">3,998<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">4,815<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementMerckKgaaMember', window );">Merck KGaA</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_RevenueTransactionPriceAmount', window );">Transaction price</a></td>
<td class="nump">21,325<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">21,325<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 21,500<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_RevenueTransactionPriceIncreaseDecrease', window );">Decrease in fees expected to be received for research and development</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">175<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated', window );">Amount of research and development fees expected to be received</a></td>
<td class="nump">6,325<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 6,325<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsTargetsDesignatedPerformanceObligationsSatisfiedNumber', window );">Number of targets with satisfied performance obligations | target</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="nump">$ 11<span></span>
</td>
<td class="nump">$ 800<span></span>
</td>
<td class="nump">$ 817<span></span>
</td>
<td class="nump">836<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_SupplyAgreementMerckKgaaMember', window );">Merck KGaA Supply Agreement</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">34<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,255<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ResearchAndDevelopmentExpense', window );">Research and development</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 34<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 1,255<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationArrangementsTargetsDesignatedPerformanceObligationsSatisfiedNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of designated targets for which performance obligations have been satisfied during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsTargetsDesignatedPerformanceObligationsSatisfiedNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:integerItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Estimated amount of research and development expenses received or expected to be received included in transaction price (performance obligation).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ReimbursableExpenseResearchAndDevelopmentEstimated</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_RevenueTransactionPriceAmount">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of transaction price which represents the amount of consideration the entity expects to receive for transfer of goods and services. Amount is net of estimated fees associated with research and development activities.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Increase (decrease) in transaction price during the period due to change in fees expected to be received for research and development activities.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_RevenueTransactionPriceIncreaseDecrease</td>
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<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td>xbrli:stringItemType</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ContractWithCustomerLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130531-203044<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130532-203044<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ResearchAndDevelopmentExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 985<br> -SubTopic 20<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6501960&amp;loc=d3e128462-111756<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 730<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6420194&amp;loc=d3e21568-108373<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ResearchAndDevelopmentExpense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 40<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9031-108599<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 41<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9038-108599<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130543-203045<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 42<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9054-108599<br><br>Reference 10: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130545-203045<br><br>Reference 11: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 924<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 11.L)<br> -URI http://asc.fasb.org/extlink&amp;oid=6472922&amp;loc=d3e499488-122856<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax</td>
</tr>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Indicates product and service for revenue from satisfaction of performance obligation by transferring promised product and service to customer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/exampleRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 55<br> -Paragraph 91<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121551570&amp;loc=SL49130690-203046-203046<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RevenueFromContractWithCustomerProductAndServiceExtensibleList</td>
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<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>srt-types:extensibleListItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementAndSupplyAgreementMerckKgaaMember">
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<tr>
<td><strong> Name:</strong></td>
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<td></td>
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<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementMerckKgaaMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td>na</td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980903464">
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<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements - Merck KGaA - Performance Obligation Period (Details)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
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<tr><th class="th"><div>Sep. 30, 2020</div></th></tr>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationAgreementsAbstract', window );"><strong>Collaboration agreements</strong></a></td>
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<td class="text">Revenue related to future technological improvements and joint research committee services will be recognized ratably over the respective performance period (which in the case of the joint research committee services approximates the time and cost incurred each period), which are 10 and five years, respectively.<span></span>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Description of timing for satisfying performance obligation in contract with customer. Includes, but is not limited to, as services are rendered, and upon shipment, delivery or completion of service.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 12<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130554-203045<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RevenuePerformanceObligationDescriptionOfTiming</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
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<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217987071848">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements - XMT-1522 Strategic Partnership (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="1"></th>
<th class="th" colspan="3">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Jan. 02, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Mar. 31, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ResearchAndDevelopmentExpense', window );">Research and development</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 16,546<span></span>
</td>
<td class="nump">$ 13,701<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 44,179<span></span>
</td>
<td class="nump">$ 42,610<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_DevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember', window );">XMT-1522 Agreement</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsDurationToTermination', window );">Period of time until agreement terminated</a></td>
<td class="text">30 days<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod', window );">Period of shared development costs following effective termination date</a></td>
<td class="text">30 days<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ResearchAndDevelopmentExpense', window );">Research and development</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 200<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
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<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationArrangementsDurationToTermination">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Period of time before which agreement will be terminated due to counter party serving prior written notice, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsDurationToTermination</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Period of time following effective termination date in which development costs were equally shared with counterparty under the terms of the agreement, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsSharedDevelopmentCostsEffectiveFollowingTerminationDatePeriod</td>
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<td>na</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ResearchAndDevelopmentExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 985<br> -SubTopic 20<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6501960&amp;loc=d3e128462-111756<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 730<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6420194&amp;loc=d3e21568-108373<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ResearchAndDevelopmentExpense</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_TypeOfArrangementAxis=mrsn_DevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
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<tr>
<td><strong> Period Type:</strong></td>
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<head>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980652568">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements - Takeda strategic R &amp; D partnership (Details) - 2016 Restated Tokeda Agreement<br> $ in Thousands</strong></div></th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1">3 Months Ended</th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Jan. 02, 2019</div></th>
<th class="th">
<div>Mar. 31, 2019 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Jan. 31, 2016 </div>
<div>target</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborativeArrangementsExclusiveTargetsNumber', window );">Number of targets | target</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">7<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsDurationToTermination', window );">Period of time until agreement terminated</a></td>
<td class="text">45 days<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsCostsBilled', window );">Amount of costs billed | $</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 195<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
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<div style="display: none;">
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of costs billed during the period under terms of agreement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsCostsBilled</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
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<td><strong> Data Type:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationArrangementsDurationToTermination">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Period of time before which agreement will be terminated due to counter party serving prior written notice, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsDurationToTermination</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of exclusive targets entity provided right to develop under terms of agreement as of balance sheet date.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborativeArrangementsExclusiveTargetsNumber</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983383864">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration agreements - Takeda - Accounting Analysis (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="3">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Mar. 31, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiabilityRevenueRecognized', window );">Deferred revenue recognized</a></td>
<td class="nump">$ 11<span></span>
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<td class="nump">$ 834<span></span>
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<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 817<span></span>
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<td class="nump">$ 41,550<span></span>
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<td class="text">&#160;<span></span>
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<td class="nump">4,528<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">4,528<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 7,296<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="nump">11<span></span>
</td>
<td class="nump">$ 844<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">817<span></span>
</td>
<td class="nump">$ 42,081<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_ResearchCollaborationAndCommercialLicenseAgreementTakeda2016RestatedAgreementAndDevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember', window );">2016 Restated Tokeda Agreement and XMT-1522 Agreement</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiabilityRevenueRecognized', window );">Deferred revenue recognized</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 39,965<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccountsPayableCurrent', window );">Accounts payable</a></td>
<td class="nump">$ 2,335<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 2,335<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 2,335<span></span>
</td>
</tr>
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<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccountsPayableCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.19(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccountsPayableCurrent</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerLiabilityRevenueRecognized</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 40<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9031-108599<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 41<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9038-108599<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130543-203045<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 42<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9054-108599<br><br>Reference 10: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130545-203045<br><br>Reference 11: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 924<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 11.L)<br> -URI http://asc.fasb.org/extlink&amp;oid=6472922&amp;loc=d3e499488-122856<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_TypeOfArrangementAxis=mrsn_ResearchCollaborationAndCommercialLicenseAgreementTakeda2016RestatedAgreementAndDevelopmentCollaborationAndCommercialLicenseAgreementTakedaMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
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<tr>
<td><strong> Period Type:</strong></td>
<td></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217984305832">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration Agreements - Contract Assets and Liabilities (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
<th class="th"><div>Dec. 31, 2018</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationAgreementsAbstract', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerAssetNet', window );">Contract assets</a></td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ChangeInContractAssetsAndLiabilitiesRollForward', window );"><strong>Contract liabilities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiability', window );">Deferred revenue, Balance at Beginning of Period</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">4,815<span></span>
</td>
<td class="nump">46,196<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ContractWithCustomerLiabilityIncrease', window );">Deferred revenue, Additions</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
<td class="nump">0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ContractWithCustomerLiabilityDecrease', window );">Deferred revenue, Deductions</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">817<span></span>
</td>
<td class="nump">41,550<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiability', window );">Deferred revenue, Balance at End of Period</a></td>
<td class="nump">3,998<span></span>
</td>
<td class="nump">4,646<span></span>
</td>
<td class="nump">3,998<span></span>
</td>
<td class="nump">4,646<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract', window );"><strong>Revenue recognized in the period from:</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerLiabilityRevenueRecognized', window );">Amounts included in the contract liability at the beginning of the period</a></td>
<td class="nump">11<span></span>
</td>
<td class="nump">834<span></span>
</td>
<td class="nump">817<span></span>
</td>
<td class="nump">41,550<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod', window );">Performance obligations satisfied in previous periods</a></td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ChangeInContractAssetsAndLiabilitiesRollForward">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Change In Contract Assets And Liabilities</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ChangeInContractAssetsAndLiabilitiesRollForward</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationAgreementsAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationAgreementsAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ContractWithCustomerLiabilityDecrease">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of decrease in obligation to transfer good or service to customer for which consideration has been received or is receivable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ContractWithCustomerLiabilityDecrease</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ContractWithCustomerLiabilityIncrease">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase in obligation to transfer good or service to customer for which consideration has been received or is receivable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ContractWithCustomerLiabilityIncrease</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ChangeInContractWithCustomerAssetAndLiabilityAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ContractWithCustomerAssetNet">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130531-203044<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130533-203044<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerAssetNet</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ContractWithCustomerLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130531-203044<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 45<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=121556615&amp;loc=SL49130532-203044<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ContractWithCustomerLiabilityRevenueRecognized">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 8<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130549-203045<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerLiabilityRevenueRecognized</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of revenue recognized from performance obligation satisfied or partially satisfied in previous reporting periods. Includes, but is not limited to, change in transaction price.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 12A<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL108322424-203045<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986942184">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Collaboration Agreements - Other Revenue (Details) - USD ($)<br></strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="nump">$ 11,000<span></span>
</td>
<td class="nump">$ 844,000<span></span>
</td>
<td class="nump">$ 817,000<span></span>
</td>
<td class="nump">$ 42,081,000<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember', window );">Asana BioSciences</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_CollaborationArrangementsMilestonePaymentReceivableNextMilestone', window );">Next potential milestone payment eligible to receive</a></td>
<td class="nump">2,500,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2,500,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember', window );">Asana BioSciences | Services</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems', window );"><strong>Collaboration agreements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax', window );">Collaboration revenue</a></td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 10,000<span></span>
</td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 25,000<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_CollaborationArrangementsMilestonePaymentReceivableNextMilestone">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of the next potential milestone the company will be eligible to receive.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_CollaborationArrangementsMilestonePaymentReceivableNextMilestone</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 30<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8906-108599<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 40<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9031-108599<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 41<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9038-108599<br><br>Reference 4: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 5: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 32<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8933-108599<br><br>Reference 6: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130543-203045<br><br>Reference 7: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 8: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 22<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e8736-108599<br><br>Reference 9: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 280<br> -SubTopic 10<br> -Section 50<br> -Paragraph 42<br> -URI http://asc.fasb.org/extlink&amp;oid=120311839&amp;loc=d3e9054-108599<br><br>Reference 10: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 606<br> -SubTopic 10<br> -Section 50<br> -Paragraph 5<br> -URI http://asc.fasb.org/extlink&amp;oid=121604090&amp;loc=SL49130545-203045<br><br>Reference 11: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 924<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 11.L)<br> -URI http://asc.fasb.org/extlink&amp;oid=6472922&amp;loc=d3e499488-122856<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_TypeOfArrangementAxis=mrsn_CollaborationAndCommercialLicenseAgreementAsanaBioSciencesMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
<td></td>
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<tr>
<td><strong> Period Type:</strong></td>
<td></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_srt_ProductOrServiceAxis=us-gaap_ServiceMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">srt_ProductOrServiceAxis=us-gaap_ServiceMember</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
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<td><strong> Period Type:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983639208">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Fair value measurements (Details)<br> $ in Thousands</strong></div></th>
<th class="th">
<div>Dec. 31, 2019 </div>
<div>USD ($)</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">$ 37,439<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AssetsFairValueDisclosure', window );">Total assets regularly measured and carried at fair value</a></td>
<td class="nump">37,439<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Commercial paper</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">11,940<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Corporate bonds</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">12,010<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | U.S. Treasuries</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">13,489<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AssetsFairValueDisclosure', window );">Total assets regularly measured and carried at fair value</a></td>
<td class="nump">13,489<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial paper</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasuries</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">13,489<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Other Observable Inputs (Level 2)</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AssetsFairValueDisclosure', window );">Total assets regularly measured and carried at fair value</a></td>
<td class="nump">23,950<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Other Observable Inputs (Level 2) | Commercial paper</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">11,940<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate bonds</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">12,010<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Treasuries</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Unobservable Inputs (Level&#160;3)</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AssetsFairValueDisclosure', window );">Total assets regularly measured and carried at fair value</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Unobservable Inputs (Level&#160;3) | Commercial paper</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Unobservable Inputs (Level&#160;3) | Corporate bonds</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember', window );">Recurring basis | Significant Unobservable Inputs (Level&#160;3) | U.S. Treasuries</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems', window );"><strong>Fair value measurements</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Marketable securities</a></td>
<td class="nump">$ 0<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AssetsFairValueDisclosure">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 820<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=117815213&amp;loc=d3e19207-110258<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AssetsFairValueDisclosure</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(6))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 326<br> -SubTopic 30<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121558606&amp;loc=SL82898722-210454<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121553693&amp;loc=d3e26610-111562<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (aa)<br> -URI http://asc.fasb.org/extlink&amp;oid=121645371&amp;loc=d3e27161-111563<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleSecuritiesDebtSecurities</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
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</table></div>
</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FairValueByAssetClassAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByAssetClassAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
<td></td>
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<td><strong> Period Type:</strong></td>
<td></td>
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</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByAssetClassAxis=us-gaap_CorporateDebtSecuritiesMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
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<tr>
<td><strong> Period Type:</strong></td>
<td></td>
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</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FairValueByAssetClassAxis=us-gaap_USTreasurySecuritiesMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByAssetClassAxis=us-gaap_USTreasurySecuritiesMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
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</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217984201400">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Marketable securities (Details)<br> $ in Thousands</strong></div></th>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>security</div>
</th>
<th class="th">
<div>Dec. 31, 2019 </div>
<div>USD ($)</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems', window );"><strong>Debt Securities, Available-for-sale [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions', window );">Number of securities in unrealized loss position | security</a></td>
<td class="nump">0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract', window );"><strong>Marketable securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis', window );">Amortized Cost</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 37,414<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax', window );">Gross Unrealized Gains</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">25<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax', window );">Gross Unrealized Losses</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Fair Value</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">37,439<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember', window );">Commercial paper</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract', window );"><strong>Marketable securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis', window );">Amortized Cost</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">11,940<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax', window );">Gross Unrealized Gains</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax', window );">Gross Unrealized Losses</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Fair Value</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">11,940<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember', window );">Corporate bonds</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract', window );"><strong>Marketable securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis', window );">Amortized Cost</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">11,990<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax', window );">Gross Unrealized Gains</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">20<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax', window );">Gross Unrealized Losses</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Fair Value</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">12,010<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember', window );">U.S. Treasuries</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract', window );"><strong>Marketable securities</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis', window );">Amortized Cost</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">13,484<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax', window );">Gross Unrealized Gains</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">5<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax', window );">Gross Unrealized Losses</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities', window );">Fair Value</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 13,489<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121645371&amp;loc=d3e27161-111563<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)<br> -URI http://asc.fasb.org/extlink&amp;oid=121645371&amp;loc=d3e27161-111563<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121645371&amp;loc=d3e27161-111563<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 326<br> -SubTopic 30<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121558606&amp;loc=SL82898722-210454<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AvailableForSaleSecuritiesDebtSecurities">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(6))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 326<br> -SubTopic 30<br> -Section 45<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=121558606&amp;loc=SL82898722-210454<br><br>Reference 3: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121553693&amp;loc=d3e26610-111562<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (aa)<br> -URI http://asc.fasb.org/extlink&amp;oid=121645371&amp;loc=d3e27161-111563<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleSecuritiesDebtSecurities</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 320<br> -SubTopic 10<br> -Section 50<br> -Paragraph 6<br> -Subparagraph (b)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=121645371&amp;loc=d3e27290-111563<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 326<br> -SubTopic 30<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (b)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=121582814&amp;loc=SL82922888-210455<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:integerItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
<td></td>
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<tr>
<td><strong> Period Type:</strong></td>
<td></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td>na</td>
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<DOCUMENT>
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<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217978717512">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Accrued Expenses (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccruedLiabilitiesCurrentAbstract', window );"><strong>Accrued Liabilities, Current [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeRelatedLiabilitiesCurrent', window );">Accrued payroll and related expenses</a></td>
<td class="nump">$ 3,647<span></span>
</td>
<td class="nump">$ 4,037<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_AccruedPreclinicalAndClinicalExpensesCurrent', window );">Accrued preclinical, manufacturing and clinical expenses</a></td>
<td class="nump">6,600<span></span>
</td>
<td class="nump">4,230<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_AccruedProfessionalFeesAndInsuranceCurrent', window );">Accrued professional fees and insurance</a></td>
<td class="nump">861<span></span>
</td>
<td class="nump">675<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherAccruedLiabilitiesCurrent', window );">Accrued other</a></td>
<td class="nump">65<span></span>
</td>
<td class="nump">44<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AccruedLiabilitiesCurrent', window );">Total</a></td>
<td class="nump">$ 11,173<span></span>
</td>
<td class="nump">$ 8,986<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_AccruedPreclinicalAndClinicalExpensesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Carrying value as of the balance sheet date of obligations incurred through that date and payable for preclinical, manufacturing and clinical expense. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_AccruedPreclinicalAndClinicalExpensesCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_AccruedProfessionalFeesAndInsuranceCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received and insurance. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_AccruedProfessionalFeesAndInsuranceCurrent</td>
</tr>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccruedLiabilitiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.20)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccruedLiabilitiesCurrent</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
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<td>xbrli:monetaryItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AccruedLiabilitiesCurrentAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AccruedLiabilitiesCurrentAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_EmployeeRelatedLiabilitiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.20)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_EmployeeRelatedLiabilitiesCurrent</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OtherAccruedLiabilitiesCurrent">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.20)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6911-107765<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 9<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e7018-107765<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section 45<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=121566466&amp;loc=d3e6935-107765<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OtherAccruedLiabilitiesCurrent</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<DOCUMENT>
<TYPE>XML
<SEQUENCE>57
<FILENAME>R47.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217990753448">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Debt - Agreement Narrative (Details) - USD ($)<br></strong></div></th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Aug. 28, 2020</div></th>
<th class="th"><div>May 08, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DeferredFinanceCostsNet', window );">Unamortized issuance costs</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 262,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 262,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentCarryingAmount', window );">Outstanding debt</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">5,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">5,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_InterestExpenseDebt', window );">Interest expense</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">60,000<span></span>
</td>
<td class="nump">$ 51,000<span></span>
</td>
<td class="nump">173,000<span></span>
</td>
<td class="nump">$ 64,000<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_ExistingCreditFacilityMember', window );">Existing Credit Facility | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromLinesOfCredit', window );">Proceeds from line of credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DeferredFinanceCostsNet', window );">Unamortized issuance costs</a></td>
<td class="nump">$ 139,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_ExistingCreditFacilityMember', window );">Existing Credit Facility | Minimum | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentInterestRateStatedPercentage', window );">Debt interest rate percentage</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">4.00%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_ExistingCreditFacilityMember', window );">Existing Credit Facility | Minimum | Prime Rate | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1', window );">Basis spread on variable rate</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1.50%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember', window );">Amendment To Credit Facility | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromLinesOfCredit', window );">Proceeds from line of credit</a></td>
<td class="nump">5,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity', window );">Maximum borrowing capacity</a></td>
<td class="nump">$ 30,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal', window );">Final payment as percentage of original principal amount</a></td>
<td class="nump">5.50%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_DebtInstrumentDebtDefaultAdditionalRate', window );">Additional rate in event of default</a></td>
<td class="nump">5.00%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DeferredFinanceCostsGross', window );">Unamortized issuance costs</a></td>
<td class="nump">$ 17,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentCarryingAmount', window );">Outstanding debt</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember', window );">Amendment To Credit Facility | Line of Credit | Prior To August 28, 2021</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_DebtInstrumentPrepaymentFeePercentage', window );">Prepayment fee percent</a></td>
<td class="nump">3.00%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember', window );">Amendment To Credit Facility | Line of Credit | Between August 28, 2021 And August 28, 2022</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_DebtInstrumentPrepaymentFeePercentage', window );">Prepayment fee percent</a></td>
<td class="nump">2.00%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember', window );">Amendment To Credit Facility | Line of Credit | Between August 28, 2022 And November 1, 2024</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_DebtInstrumentPrepaymentFeePercentage', window );">Prepayment fee percent</a></td>
<td class="nump">1.00%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember', window );">Amendment To Credit Facility | Minimum | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentInterestRateStatedPercentage', window );">Debt interest rate percentage</a></td>
<td class="nump">4.25%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember', window );">Amendment To Credit Facility | Minimum | Prime Rate | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1', window );">Basis spread on variable rate</a></td>
<td class="num">(1.00%)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheOneMember', window );">Amended Credit Facility, Tranche One | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity', window );">Maximum borrowing capacity</a></td>
<td class="nump">$ 25,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheTwoMember', window );">Amended Credit Facility, Tranche Two | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity', window );">Maximum borrowing capacity</a></td>
<td class="nump">25,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheThreeMember', window );">Amended Credit Facility, Tranche Three | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity', window );">Maximum borrowing capacity</a></td>
<td class="nump">25,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheFourMember', window );">Amended Credit Facility, Tranche Four | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity', window );">Maximum borrowing capacity</a></td>
<td class="nump">25,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheFiveMember', window );">Amended Credit Facility, Tranche Five | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity', window );">Maximum borrowing capacity</a></td>
<td class="nump">25,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheSixMember', window );">Amended Credit Facility, Tranche Six | Line of Credit</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentLineItems', window );"><strong>Debt</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit', window );">Line of credit, increase limit</a></td>
<td class="nump">$ 5,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_DebtInstrumentDebtDefaultAdditionalRate">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Represents the additional percentage rate of interest in event of default under debt instrument.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_DebtInstrumentDebtDefaultAdditionalRate</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Represents the final payment as percentage of original principal amount.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_DebtInstrumentFinalPaymentPercentageOfOriginalPrincipal</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_DebtInstrumentPrepaymentFeePercentage">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Represents the percentage of prepayment fee under debt instrument.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_DebtInstrumentPrepaymentFeePercentage</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line Of Credit Facility, Accordian Feature, Increase Limit</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_LineOfCreditFacilityAccordianFeatureIncreaseLimit</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Percentage points added to the reference rate to compute the variable rate on the debt instrument.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentBasisSpreadOnVariableRate1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentCarryingAmount">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (b)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120520924&amp;loc=SL6031897-161870<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(22))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentCarryingAmount</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentInterestRateStatedPercentage">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Contractual interest rate for funds borrowed, under the debt agreement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.22(a)(1))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentInterestRateStatedPercentage</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DeferredFinanceCostsGross">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 30<br> -Section 45<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=119993939&amp;loc=d3e28555-108399<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DeferredFinanceCostsGross</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DeferredFinanceCostsNet">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 30<br> -Section 45<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=119993939&amp;loc=d3e28555-108399<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DeferredFinanceCostsNet</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_InterestExpenseDebt">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of the cost of borrowed funds accounted for as interest expense for debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120520924&amp;loc=SL6036836-161870<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 220<br> -SubTopic 10<br> -Section S99<br> -Paragraph 2<br> -Subparagraph (SX 210.5-03.8)<br> -URI http://asc.fasb.org/extlink&amp;oid=120395209&amp;loc=SL114868664-224227<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_InterestExpenseDebt</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.19(b),22(b))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProceedsFromLinesOfCredit">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3255-108585<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.4-08.(f))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e23780-122690<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProceedsFromLinesOfCredit</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_ExistingCreditFacilityMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_ExistingCreditFacilityMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_srt_RangeAxis=srt_MinimumMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">srt_RangeAxis=srt_MinimumMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_VariableRateAxis=us-gaap_PrimeRateMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_VariableRateAxis=us-gaap_PrimeRateMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_DebtCovenantPeriodAxis=mrsn_PriorToAugust282021Member">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_DebtCovenantPeriodAxis=mrsn_PriorToAugust282021Member</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_DebtCovenantPeriodAxis=mrsn_BetweenAugust282021AndAugust282022Member">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_DebtCovenantPeriodAxis=mrsn_BetweenAugust282021AndAugust282022Member</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_DebtCovenantPeriodAxis=mrsn_BetweenAugust282022AndNovember12024Member">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_DebtCovenantPeriodAxis=mrsn_BetweenAugust282022AndNovember12024Member</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheOneMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheOneMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheTwoMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheTwoMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheThreeMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheThreeMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheFourMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheFourMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheFiveMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheFiveMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentAxis=mrsn_AmendedCreditFacilityTrancheSixMember</td>
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<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217980784744">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Debt - Components (Details)<br> $ in Thousands</strong></div></th>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($)</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtDisclosureAbstract', window );"><strong>Debt Disclosure [Abstract]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentCarryingAmount', window );">Outstanding debt</a></td>
<td class="nump">$ 5,200<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DeferredFinanceCostsNet', window );">Debt financing costs, net of accretion</a></td>
<td class="num">(262)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentUnamortizedPremium', window );">Accretion related to final payment</a></td>
<td class="nump">6<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebt', window );">Long-term Debt</a></td>
<td class="nump">$ 4,944<span></span>
</td>
</tr>
</table>
<div style="display: none;">
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtDisclosureAbstract</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td>xbrli:stringItemType</td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (b)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120520924&amp;loc=SL6031897-161870<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(22))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentCarryingAmount</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td>xbrli:monetaryItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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</div></td></tr>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after accumulated amortization, of debt premium.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 30<br> -Section 55<br> -Paragraph 8<br> -URI http://asc.fasb.org/extlink&amp;oid=114775985&amp;loc=d3e28878-108400<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 30<br> -Section 45<br> -Paragraph 1A<br> -URI http://asc.fasb.org/extlink&amp;oid=119993939&amp;loc=d3e28541-108399<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentUnamortizedPremium</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.17)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 835<br> -SubTopic 30<br> -Section 45<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=119993939&amp;loc=d3e28555-108399<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DeferredFinanceCostsNet</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
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<td><strong> Balance Type:</strong></td>
<td>debit</td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LongTermDebt">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (b)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=120520924&amp;loc=SL6031897-161870<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(a)(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(22))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebt</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217978628504">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Debt - Future payments (Details)<br> $ in Thousands</strong></div></th>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($)</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_MaturitiesOfLongTermDebtAbstract', window );"><strong>Estimated future principal payments</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear', window );">2020 (excluding the nine months ended September 30, 2020)</a></td>
<td class="nump">$ 0<span></span>
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<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths', window );">2021</a></td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo', window );">2022</a></td>
<td class="nump">1,213<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree', window );">2023</a></td>
<td class="nump">2,080<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour', window );">2024</a></td>
<td class="nump">1,907<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_DebtInstrumentCarryingAmount', window );">Total debt</a></td>
<td class="nump">$ 5,200<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_DebtInstrumentCarryingAmount">
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 20<br> -Section 50<br> -Paragraph 4<br> -Subparagraph (b)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120520924&amp;loc=SL6031897-161870<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 944<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.7-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120400017&amp;loc=d3e572229-122910<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(22))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 942<br> -SubTopic 210<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.9-03(16))<br> -URI http://asc.fasb.org/extlink&amp;oid=120398452&amp;loc=d3e534808-122878<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_DebtInstrumentCarryingAmount</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 3<br> -Subparagraph (SX 210.12-04.(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e24072-122690<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6802200&amp;loc=d3e1835-112601<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Data Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 3<br> -Subparagraph (SX 210.12-04.(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e24072-122690<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6802200&amp;loc=d3e1835-112601<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 3<br> -Subparagraph (SX 210.12-04.(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e24072-122690<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6802200&amp;loc=d3e1835-112601<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 3<br> -Subparagraph (SX 210.12-04.(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e24072-122690<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 470<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -URI http://asc.fasb.org/extlink&amp;oid=6802200&amp;loc=d3e1835-112601<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in remainder of current fiscal year.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 235<br> -SubTopic 10<br> -Section S99<br> -Paragraph 3<br> -Subparagraph (SX 210.12-04.(a))<br> -URI http://asc.fasb.org/extlink&amp;oid=120395691&amp;loc=d3e24072-122690<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217982429752">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Stockholders' Equity - Preferred stock (Details) - shares<br></strong></div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
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<tr class="re">
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<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
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<td class="nump">25,000,000<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PreferredStockSharesIssued', window );">Preferred stock, shares issued (in shares)</a></td>
<td class="nump">0<span></span>
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<td class="text">&#160;<span></span>
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<div style="display: none;">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PreferredStockSharesIssued</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986584296">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stockholders' Equity - At-the-market equity and follow on offering programs (Details) - USD ($)<br></strong></div></th>
<th class="th" colspan="2">1 Months Ended</th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
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<tr>
<th class="th"><div>Jun. 30, 2020</div></th>
<th class="th"><div>Apr. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>May 31, 2020</div></th>
<th class="th"><div>Jul. 31, 2018</div></th>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2018ATMMember', window );">At Market Equity Offering Program (2018 ATM)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockLineItems', window );"><strong>Offering program</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuanceProgramAuthorizedAmount', window );">Amount of shares authorized to be offered and sold</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 75,000,000<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Number of shares sold (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">10,900,599<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ProceedsFromIssuanceOfCommonStockGross', window );">Proceeds from issuance of common stock, gross</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 65,153,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts', window );">Proceeds from stock issuance, net of issuance costs</a></td>
<td class="text">&#160;<span></span>
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<td class="nump">$ 62,976,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram559PerShareMember', window );">At Market Equity Offering Program, 5.59 per Share</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockLineItems', window );"><strong>Offering program</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Number of shares sold (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">8,938,599<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesIssuedPricePerShare', window );">Shares sold, price per share (in dollars per share)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 5.59<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram774PerShareMember', window );">At Market Equity Offering Program, 7.74 per Share</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockLineItems', window );"><strong>Offering program</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Number of shares sold (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,962,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesIssuedPricePerShare', window );">Shares sold, price per share (in dollars per share)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 7.74<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2020ATMMember', window );">At Market Equity Offering Program (2020 ATM)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockLineItems', window );"><strong>Offering program</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_StockIssuanceProgramAuthorizedAmount', window );">Amount of shares authorized to be offered and sold</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 100,000,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesIssued', window );">Shares sold to date (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember', window );">Public Stock Offering</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SubsidiarySaleOfStockLineItems', window );"><strong>Offering program</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues', window );">Number of shares sold (in shares)</a></td>
<td class="nump">9,200,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharesIssuedPricePerShare', window );">Shares sold, price per share (in dollars per share)</a></td>
<td class="nump">$ 19.00<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ProceedsFromIssuanceOfCommonStockGross', window );">Proceeds from issuance of common stock, gross</a></td>
<td class="nump">$ 174,800,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts', window );">Proceeds from stock issuance, net of issuance costs</a></td>
<td class="nump">$ 163,991,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ProceedsFromIssuanceOfCommonStockGross">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The gross proceeds from the additional capital contribution to the entity.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ProceedsFromIssuanceOfCommonStockGross</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The net proceeds from the additional capital contribution to the entity after deducting fees, commissions and other expenses.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ProceedsFromIssuanceOfCommonStockNetOfStockIssuanceCosts</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_StockIssuanceProgramAuthorizedAmount">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of common stock shares authorized to be issued under the program.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_StockIssuanceProgramAuthorizedAmount</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SharesIssued">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SharesIssued</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SharesIssuedPricePerShare">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Per share or per unit amount of equity securities issued.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SharesIssuedPricePerShare</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StockIssuedDuringPeriodSharesNewIssues">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of new stock issued during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StockIssuedDuringPeriodSharesNewIssues</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2018ATMMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2018ATMMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram559PerShareMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram559PerShareMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram774PerShareMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram774PerShareMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2020ATMMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_AtMarketEquityOfferingProgram2020ATMMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SubsidiarySaleOfStockAxis=mrsn_PublicStockOfferingMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>62
<FILENAME>R52.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
							function toggleNextSibling (e) {
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							e.nextSibling.style.display='block';
							} else { e.nextSibling.style.display='none'; }
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</head>
<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217978777512">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stockholders' Equity - Warrants (Details) - $ / shares<br></strong></div></th>
<th class="th" colspan="1">12 Months Ended</th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Dec. 31, 2013</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_WarrantsAndRightsNoteDisclosureAbstract', window );"><strong>Warrants</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued', window );">Number of shares into which warrant issued during period may be converted (in shares)</a></td>
<td class="nump">129,491<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1', window );">Warrant exercise price per share (in dollars per share)</a></td>
<td class="nump">$ 0.05<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ContractualLifeOfWarrants', window );">Contractual life of warrants</a></td>
<td class="text">10 years<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights', window );">Number of shares of common stock into which warrants may be converted</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">39,474<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of securities into which the class of warrant or right issued during the period may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ClassOfWarrantOrRightSecuritiesCalledByWarrantsOrRightsNumberIssued</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ContractualLifeOfWarrants">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The contractual life of warrants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ContractualLifeOfWarrants</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Exercise price per share or per unit of warrants or rights outstanding.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21475-112644<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21475-112644<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_WarrantsAndRightsNoteDisclosureAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_WarrantsAndRightsNoteDisclosureAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>63
<FILENAME>R53.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
							function toggleNextSibling (e) {
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							e.nextSibling.style.display='block';
							} else { e.nextSibling.style.display='none'; }
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</head>
<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983910088">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Stockholders' Equity - Exchange Warrants (Details) - $ / shares<br></strong></div></th>
<th class="th"><div>Mar. 02, 2020</div></th>
<th class="th"><div>Nov. 26, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Dec. 31, 2013</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfStockLineItems', window );"><strong>Class of Stock [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights', window );">Number of shares of common stock into which warrants may be converted</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">39,474<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1', window );">Warrant exercise price per share (in dollars per share)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 0.05<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember', window );">Common&#160;Stock</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfStockLineItems', window );"><strong>Class of Stock [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_WarrantsExercisedInPeriod', window );">Exercise of common stock warrant in exchange for common stock (in shares)</a></td>
<td class="nump">2,574,971<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=mrsn_WarrantTwoMember', window );">Warrant Two</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfStockLineItems', window );"><strong>Class of Stock [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants', window );">Aggregate common stock exchanged (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2,575,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights', window );">Number of shares of common stock into which warrants may be converted</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2,575,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1', window );">Warrant exercise price per share (in dollars per share)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 0.0001<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of common shares exchanged for warrants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ClassOfWarrantOrRightSharesExchangedForWarrants</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_WarrantsExercisedInPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Shares of stock issued as a result of the exercise of warrants.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_WarrantsExercisedInPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ClassOfStockLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ClassOfStockLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Exercise price per share or per unit of warrants or rights outstanding.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21475-112644<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 3<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21475-112644<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementEquityComponentsAxis=mrsn_WarrantTwoMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementEquityComponentsAxis=mrsn_WarrantTwoMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
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<head>
<title></title>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986513192">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stockholders' Equity - Common stock (Details)<br></strong></div></th>
<th class="th" colspan="1">9 Months Ended</th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>vote </div>
<div>shares</div>
</th>
<th class="th">
<div>Dec. 31, 2019 </div>
<div>shares</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract', window );"><strong>Common stock</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="nump">6,995,704<span></span>
</td>
<td class="nump">7,782,582<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember', window );">Common&#160;Stock</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract', window );"><strong>Common stock</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_NumberOfVotesPerCommonShare', window );">Number of votes for each shares held | vote</a></td>
<td class="nump">1<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=us-gaap_DeferredCompensationShareBasedPaymentsMember', window );">Share-based payments | Stock options</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract', window );"><strong>Common stock</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="nump">6,215,368<span></span>
</td>
<td class="nump">4,720,772<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=us-gaap_DeferredCompensationShareBasedPaymentsMember', window );">Share-based payments | Restricted stock units</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract', window );"><strong>Common stock</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="nump">740,862<span></span>
</td>
<td class="nump">447,336<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=us-gaap_WarrantMember', window );">Warrants</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract', window );"><strong>Common stock</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="nump">39,474<span></span>
</td>
<td class="nump">39,474<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StatementEquityComponentsAxis=mrsn_ExchangeWarrantsMember', window );">Exchange warrants</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract', window );"><strong>Common stock</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="nump">0<span></span>
</td>
<td class="nump">2,575,000<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_NumberOfVotesPerCommonShare">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Represents the number of votes for each shares held.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_NumberOfVotesPerCommonShare</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:integerItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Aggregate number of common shares reserved for future issuance.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.29)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockCapitalSharesReservedForFutureIssuance</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockNumberOfSharesParValueAndOtherDisclosuresAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementEquityComponentsAxis=us-gaap_DeferredCompensationShareBasedPaymentsMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementEquityComponentsAxis=us-gaap_DeferredCompensationShareBasedPaymentsMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember</td>
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<tr>
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<tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementEquityComponentsAxis=us-gaap_WarrantMember</td>
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<td><strong> Data Type:</strong></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementEquityComponentsAxis=mrsn_ExchangeWarrantsMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementEquityComponentsAxis=mrsn_ExchangeWarrantsMember</td>
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<tr>
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<td></td>
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<DOCUMENT>
<TYPE>XML
<SEQUENCE>65
<FILENAME>R55.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217990661976">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Plans narrative (Details) - 2017 Plan - shares<br></strong></div></th>
<th class="th" colspan="2">1 Months Ended</th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Jan. 31, 2020</div></th>
<th class="th"><div>Jun. 30, 2017</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized', window );">Number of shares authorized (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2,255,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum', window );">Cumulative annual increase in number of shares issuable (as a percent)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">4.00%<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized', window );">Additional shares authorized (in shares)</a></td>
<td class="nump">1,815,520<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant', window );">Number of shares available for future issuance (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,320,916<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross', window );">Number of options granted in period (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">2,165,306<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The number of grants made during the period for share options (or share units) and for other than stock (or unit) options, including but not limited to, restricted stock options (or units). This amount does not include options granted as part of an inducement award.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardGrantsInPeriodGross</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of additional shares authorized for issuance under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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</table></div>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares authorized for issuance under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (a)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PlanNameAxis=mrsn_StockIncentivePlan2017Member</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
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<td><strong> Period Type:</strong></td>
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</tr>
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<DOCUMENT>
<TYPE>XML
<SEQUENCE>66
<FILENAME>R56.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217987241384">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Inducement awards narrative (Details) - shares<br></strong></div></th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 02, 2020</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross', window );">Granted (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">1,960,374<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PlanNameAxis=mrsn_InducementAwardProgramMember', window );">Inducement Award Program</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross', window );">Granted (in shares)</a></td>
<td class="nump">120,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PlanNameAxis=mrsn_InducementAwardProgramMember', window );">Inducement Award Program | Maximum</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod', window );">Expiration period</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">10 years<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PlanNameAxis=mrsn_InducementAwardProgramMember', window );">Inducement Award Program | Stock options</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1', window );">Vesting period (in years)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">4 years<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (a)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1</td>
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<tr>
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<td>us-gaap_</td>
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<td>xbrli:durationItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems</td>
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<td>xbrli:stringItemType</td>
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<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Gross number of share options (or share units) granted during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td>xbrli:sharesItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (a)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
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<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td>duration</td>
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</table></div>
</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PlanNameAxis=mrsn_InducementAwardProgramMember</td>
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<td>na</td>
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<td><strong> Balance Type:</strong></td>
<td></td>
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<td><strong> Period Type:</strong></td>
<td></td>
</tr>
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</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_srt_RangeAxis=srt_MaximumMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">srt_RangeAxis=srt_MaximumMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td>na</td>
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<td></td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<td><strong> Balance Type:</strong></td>
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<tr>
<td><strong> Period Type:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217986680520">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Activity under stock option plan (Details)<br> $ / shares in Units, $ in Thousands</strong></div></th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($) </div>
<div>$ / shares </div>
<div>shares</div>
</th>
<th class="th">
<div>Sep. 30, 2019 </div>
<div>USD ($) </div>
<div>$ / shares</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward', window );"><strong>Number of&#160;Shares</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber', window );">Outstanding at beginning of period (in shares) | shares</a></td>
<td class="nump">4,720,772<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross', window );">Granted (in shares) | shares</a></td>
<td class="nump">1,960,374<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised', window );">Exercised (in shares) | shares</a></td>
<td class="num">(338,069)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod', window );">Cancelled (in shares) | shares</a></td>
<td class="num">(127,709)<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber', window );">Outstanding at end of period (in shares) | shares</a></td>
<td class="nump">6,215,368<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber', window );">Options exercisable, at end of period (in shares) | shares</a></td>
<td class="nump">3,256,514<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward', window );"><strong>Weighted- Average Exercise&#160;Price</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice', window );">Outstanding at beginning of period (in dollars per share)</a></td>
<td class="nump">$ 5.24<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice', window );">Granted (in dollars per share)</a></td>
<td class="nump">9.41<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice', window );">Exercised (in dollars per share)</a></td>
<td class="nump">5.13<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice', window );">Cancelled (in dollars per share)</a></td>
<td class="nump">7.70<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice', window );">Outstanding at end of period (in dollars per share)</a></td>
<td class="nump">6.52<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice', window );">Options exercisable, at end of period (in dollars per share)</a></td>
<td class="nump">4.87<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract', window );"><strong>Additional Disclosures</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue', window );">Weighted-average grant date fair value of options granted (in dollars per share)</a></td>
<td class="nump">$ 6.17<span></span>
</td>
<td class="nump">$ 2.47<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ProceedsFromStockOptionsExercised', window );">Cash received from the exercise of stock options (in dollars) | $</a></td>
<td class="nump">$ 1,732<span></span>
</td>
<td class="nump">$ 121<span></span>
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</tr>
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<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ProceedsFromStockOptionsExercised">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cash inflow from exercise of option under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2A<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=SL79508275-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 230<br> -SubTopic 10<br> -Section 45<br> -Paragraph 14<br> -Subparagraph (a)<br> -URI http://asc.fasb.org/extlink&amp;oid=121586364&amp;loc=d3e3255-108585<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ProceedsFromStockOptionsExercised</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(iii)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(iii)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(iv)(4)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Gross number of share options (or share units) granted during the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (d)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of options outstanding, including both vested and non-vested options.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(i)-(ii)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(i)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Weighted average price at which option holders acquired shares when converting their stock options into shares.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>num:perShareItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of share options (or share units) exercised during the current period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(iv)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.3-04)<br> -URI http://asc.fasb.org/extlink&amp;oid=120397183&amp;loc=d3e187085-122770<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(28))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02(29))<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br><br>Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 505<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=109259400&amp;loc=d3e21463-112644<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<DOCUMENT>
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<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217991369352">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Restricted stock units (Details) - Restricted stock units - shares<br></strong></div></th>
<th class="th" colspan="2">1 Months Ended</th>
<th class="th" colspan="1">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Jan. 31, 2020</div></th>
<th class="th"><div>Jul. 31, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1', window );">Vesting period (in years)</a></td>
<td class="text">4 years<span></span>
</td>
<td class="text">2 years<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward', window );"><strong>Restricted stock units</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber', window );">Unvested at beginning of period (in shares)</a></td>
<td class="nump">447,336<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">447,336<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod', window );">Granted (in shares)</a></td>
<td class="nump">324,932<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">324,932<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod', window );">Vested (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod', window );">Forfeited (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="num">(31,406)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber', window );">Unvested at end of period (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">740,862<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (a)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(1)(iv)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(2)(iii)(1)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(2)(i)-(ii)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (c)(2)(iii)(2)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
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</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
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<DESCRIPTION>IDEA: XBRL DOCUMENT
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<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140218021507144">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Stock based compensation expense (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AllocatedShareBasedCompensationExpense', window );">Stock-based compensation expense included in total operating expenses</a></td>
<td class="nump">$ 1,918<span></span>
</td>
<td class="nump">$ 1,285<span></span>
</td>
<td class="nump">$ 5,183<span></span>
</td>
<td class="nump">$ 3,610<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncomeStatementLocationAxis=us-gaap_ResearchAndDevelopmentExpenseMember', window );">Research and development</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AllocatedShareBasedCompensationExpense', window );">Stock-based compensation expense included in total operating expenses</a></td>
<td class="nump">952<span></span>
</td>
<td class="nump">587<span></span>
</td>
<td class="nump">2,554<span></span>
</td>
<td class="nump">1,636<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_IncomeStatementLocationAxis=us-gaap_GeneralAndAdministrativeExpenseMember', window );">General and administrative</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AllocatedShareBasedCompensationExpense', window );">Stock-based compensation expense included in total operating expenses</a></td>
<td class="nump">966<span></span>
</td>
<td class="nump">698<span></span>
</td>
<td class="nump">2,629<span></span>
</td>
<td class="nump">1,974<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember', window );">Stock options</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AllocatedShareBasedCompensationExpense', window );">Stock-based compensation expense included in total operating expenses</a></td>
<td class="nump">1,520<span></span>
</td>
<td class="nump">1,055<span></span>
</td>
<td class="nump">4,025<span></span>
</td>
<td class="nump">3,240<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions', window );">Unrecognized stock compensation cost</a></td>
<td class="nump">15,007<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 15,007<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1', window );">Weighted-average amortization period of unrecognized stock compensation cost</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">2 years 6 months<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember', window );">Restricted stock units</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AllocatedShareBasedCompensationExpense', window );">Stock-based compensation expense included in total operating expenses</a></td>
<td class="nump">335<span></span>
</td>
<td class="nump">184<span></span>
</td>
<td class="nump">$ 962<span></span>
</td>
<td class="nump">184<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions', window );">Unrecognized stock compensation cost</a></td>
<td class="nump">2,269<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 2,269<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1', window );">Weighted-average amortization period of unrecognized stock compensation cost</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">2 years 7 months 6 days<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockMember', window );">Employee stock purchase plan</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems', window );"><strong>Stock options</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AllocatedShareBasedCompensationExpense', window );">Stock-based compensation expense included in total operating expenses</a></td>
<td class="nump">$ 63<span></span>
</td>
<td class="nump">$ 46<span></span>
</td>
<td class="nump">$ 196<span></span>
</td>
<td class="nump">$ 186<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AllocatedShareBasedCompensationExpense">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5047-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 14.F)<br> -URI http://asc.fasb.org/extlink&amp;oid=115993241&amp;loc=d3e301413-122809<br><br>Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (h)(1)(i)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AllocatedShareBasedCompensationExpense</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (i)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of cost to be recognized for option under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (i)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncomeStatementLocationAxis=us-gaap_ResearchAndDevelopmentExpenseMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncomeStatementLocationAxis=us-gaap_ResearchAndDevelopmentExpenseMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_IncomeStatementLocationAxis=us-gaap_GeneralAndAdministrativeExpenseMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_IncomeStatementLocationAxis=us-gaap_GeneralAndAdministrativeExpenseMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_EmployeeStockMember</td>
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<td><strong> Data Type:</strong></td>
<td>na</td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
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<DOCUMENT>
<TYPE>XML
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<DESCRIPTION>IDEA: XBRL DOCUMENT
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<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217979469192">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Fair value assumptions (Details)<br></strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
</tr>
<tr class="re">
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<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate', window );">Risk-free interest rate (as a percent)</a></td>
<td class="nump">0.40%<span></span>
</td>
<td class="nump">1.90%<span></span>
</td>
<td class="nump">1.30%<span></span>
</td>
<td class="nump">2.40%<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate', window );">Expected dividend yield</a></td>
<td class="nump">0.00%<span></span>
</td>
<td class="nump">0.00%<span></span>
</td>
<td class="nump">0.00%<span></span>
</td>
<td class="nump">0.00%<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1', window );">Expected term (years)</a></td>
<td class="text">6 years 1 month 6 days<span></span>
</td>
<td class="text">6 years 1 month 9 days<span></span>
</td>
<td class="text">6 years 14 days<span></span>
</td>
<td class="text">5 years 11 months 26 days<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate', window );">Expected stock price volatility (as a percent)</a></td>
<td class="nump">81.00%<span></span>
</td>
<td class="nump">75.00%<span></span>
</td>
<td class="nump">72.00%<span></span>
</td>
<td class="nump">74.00%<span></span>
</td>
</tr>
</table>
<div style="display: none;">
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract</td>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (f)(2)(iii)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (f)(2)(ii)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The risk-free interest rate assumption that is used in valuing an option on its own shares.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (f)(2)(iv)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>num:percentItemType</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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</table></div>
</div></td></tr>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -Subparagraph (f)(2)(i)<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br><br>Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SAB Topic 14.D.2)<br> -URI http://asc.fasb.org/extlink&amp;oid=115993241&amp;loc=d3e301413-122809<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1</td>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
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<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983733448">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Stock options - Employee stock purchase plan narrative (Details) - shares<br></strong></div></th>
<th class="th" colspan="1">1 Months Ended</th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
<th class="th" colspan="1"></th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Jan. 31, 2020</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
<th class="th"><div>Sep. 30, 2019</div></th>
<th class="th"><div>Dec. 31, 2019</div></th>
<th class="th"><div>Dec. 31, 2017</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Employee Stock Purchase Plan</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">6,995,704<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">6,995,704<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">7,782,582<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockMember', window );">Employee stock purchase plan</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems', window );"><strong>Employee Stock Purchase Plan</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance', window );">Number of shares reserved for future issuance (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">225,000<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized', window );">Additional shares authorized (in shares)</a></td>
<td class="nump">450,000<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod', window );">Number of shares issued (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">0<span></span>
</td>
<td class="nump">0<span></span>
</td>
<td class="nump">68,419<span></span>
</td>
<td class="nump">82,281<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant', window );">Number of shares available for future issuance (in shares)</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">656,666<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">656,666<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
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<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Aggregate number of common shares reserved for future issuance.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 210<br> -SubTopic 10<br> -Section S99<br> -Paragraph 1<br> -Subparagraph (SX 210.5-02.29)<br> -URI http://asc.fasb.org/extlink&amp;oid=120391452&amp;loc=d3e13212-122682<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_CommonStockCapitalSharesReservedForFutureIssuance</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of additional shares authorized for issuance under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Number of shares issued under share-based payment arrangement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 718<br> -SubTopic 10<br> -Section 50<br> -Paragraph 2<br> -URI http://asc.fasb.org/extlink&amp;oid=120381028&amp;loc=d3e5070-113901<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:sharesItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_AwardTypeAxis=us-gaap_EmployeeStockMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_AwardTypeAxis=us-gaap_EmployeeStockMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>72
<FILENAME>R62.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
							function toggleNextSibling (e) {
							if (e.nextSibling.style.display=='none') {
							e.nextSibling.style.display='block';
							} else { e.nextSibling.style.display='none'; }
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</head>
<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983227016">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Leases - Description (Details) - USD ($)<br> $ in Thousands</strong></div></th>
<th class="th" colspan="1">1 Months Ended</th>
<th class="th" colspan="1">3 Months Ended</th>
<th class="th" colspan="1"></th>
</tr>
<tr>
<th class="th"><div>Mar. 31, 2020</div></th>
<th class="th"><div>Mar. 31, 2020</div></th>
<th class="th"><div>Sep. 30, 2020</div></th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_LeasesLineItems', window );"><strong>Leases</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_TenantImprovementAllowance', window );">Tenant improvement allowance</a></td>
<td class="nump">$ 172<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets', window );">Increase in right-of-use asset</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 9,980<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability', window );">Increase in operating lease liability</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="nump">$ 9,980<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_PropertyPlantAndEquipmentByTypeAxis=mrsn_OfficeSpaceCambridgeMaMember', window );">Office space, Cambridge, MA</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_LeasesLineItems', window );"><strong>Leases</strong></a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseRenewalTerm', window );">Renewal term</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">5 years<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_LeasesLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_LeasesLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Increase (decrease) in present value of lessee's discounted obligation for lease payments from operating lease due to lease modification</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInOperatingLeaseLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of increase (decrease) in lessee's right to use underlying asset under operating lease due to lease modification</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_LesseeOperatingLeaseModificationIncreaseDecreaseInRightOfUseAssets</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_TenantImprovementAllowance">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The amount of allowance granted and reimbursable by the landlord to a tenant to entice tenant to move into landlord's building which will enable the tenant to prepare the leased premises for tenants occupancy.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_TenantImprovementAllowance</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>debit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseRenewalTerm">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 3<br> -Subparagraph (a)(3)<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918673-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseRenewalTerm</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:durationItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_PropertyPlantAndEquipmentByTypeAxis=mrsn_OfficeSpaceCambridgeMaMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_PropertyPlantAndEquipmentByTypeAxis=mrsn_OfficeSpaceCambridgeMaMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>73
<FILENAME>R63.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
							function toggleNextSibling (e) {
							if (e.nextSibling.style.display=='none') {
							e.nextSibling.style.display='block';
							} else { e.nextSibling.style.display='none'; }
							}</script>
</head>
<body>
<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983422728">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Leases - Future minimum lease payments (Details)<br> $ in Thousands</strong></div></th>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($)</div>
</th>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract', window );"><strong>Operating leases</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear', window );">2020 (excluding the nine months ended September 30, 2020)</a></td>
<td class="nump">$ 604<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths', window );">2021</a></td>
<td class="nump">2,772<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo', window );">2022</a></td>
<td class="nump">2,843<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree', window );">2023</a></td>
<td class="nump">2,928<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour', window );">2024 and thereafter</a></td>
<td class="nump">6,904<span></span>
</td>
</tr>
<tr class="reu">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue', window );">Total lease payments</a></td>
<td class="nump">16,051<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount', window );">Present value adjustment</a></td>
<td class="num">(4,165)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OperatingLeaseLiability', window );">Present value of lease liabilities</a></td>
<td class="nump">11,886<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract', window );"><strong>Finance leases</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear', window );">2020 (excluding the three months ended June 30, 2020)</a></td>
<td class="nump">29<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths', window );">2021</a></td>
<td class="nump">116<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo', window );">2022</a></td>
<td class="nump">84<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree', window );">2023</a></td>
<td class="nump">74<span></span>
</td>
</tr>
<tr class="re">
<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour', window );">2024 and thereafter</a></td>
<td class="nump">18<span></span>
</td>
</tr>
<tr class="rou">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityPaymentsDue', window );">Total lease payments</a></td>
<td class="nump">321<span></span>
</td>
</tr>
<tr class="re">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount', window );">Present value adjustment</a></td>
<td class="num">(30)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_FinanceLeaseLiability', window );">Total finance lease liability</a></td>
<td class="nump">$ 291<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payments for finance lease, due year four and after fourth fiscal year following current fiscal year.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_FinanceLeaseLiabilityPaymentsDueYearFourAndAfterYearFour</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payments for operating lease, due year four and after fourth fiscal year following current fiscal year.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_LesseeOperatingLeaseLiabilityPaymentsDueYearFourAndAfterYearFour</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>mrsn_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilitiesPaymentsDueAbstract</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Present value of lessee's discounted obligation for lease payments from finance lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br><br>Reference 2: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121603541&amp;loc=SL77918627-209977<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiability</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilityPaymentsDue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payments for finance lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilityPaymentsDue</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilityPaymentsDueNextTwelveMonths</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilityPaymentsDueYearThree</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilityPaymentsDueYearTwo</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in remainder of current fiscal year.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for operating lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
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<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
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</table></div>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payment for operating lease having initial or remaining lease term in excess of one year to be paid in remainder of current fiscal year.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<tr>
<td><strong> Data Type:</strong></td>
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<td><strong> Balance Type:</strong></td>
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<td><strong> Period Type:</strong></td>
<td>instant</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 50<br> -Paragraph 6<br> -URI http://asc.fasb.org/extlink&amp;oid=121609121&amp;loc=SL77918701-209980<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<tr>
<td><strong> Period Type:</strong></td>
<td>instant</td>
</tr>
</table></div>
</div></td></tr>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract</td>
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<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Balance Type:</strong></td>
<td>na</td>
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<td><strong> Period Type:</strong></td>
<td>duration</td>
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<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_OperatingLeaseLiability">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Present value of lessee's discounted obligation for lease payments from operating lease.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/disclosureRef<br> -Publisher FASB<br> -Name Accounting Standards Codification<br> -Topic 842<br> -SubTopic 20<br> -Section 45<br> -Paragraph 1<br> -Subparagraph (b)<br> -URI http://asc.fasb.org/extlink&amp;oid=121603541&amp;loc=SL77918627-209977<br></p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_OperatingLeaseLiability</td>
</tr>
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<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>us-gaap_</td>
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<td><strong> Data Type:</strong></td>
<td>xbrli:monetaryItemType</td>
</tr>
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<td><strong> Balance Type:</strong></td>
<td>credit</td>
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<td><strong> Period Type:</strong></td>
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<span style="display: none;">v3.20.2</span><table class="report" border="0" cellspacing="2" id="idm140217983388968">
<tr>
<th class="tl" colspan="1" rowspan="2"><div style="width: 200px;"><strong>Commitments - License agreements (Details)<br></strong></div></th>
<th class="th" colspan="2">3 Months Ended</th>
<th class="th" colspan="2">9 Months Ended</th>
</tr>
<tr>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Sep. 30, 2019 </div>
<div>USD ($)</div>
</th>
<th class="th">
<div>Sep. 30, 2020 </div>
<div>USD ($) </div>
<div>company</div>
</th>
<th class="th">
<div>Sep. 30, 2019 </div>
<div>USD ($)</div>
</th>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherCommitmentsLineItems', window );"><strong>Commitments</strong></a></td>
<td class="text">&#160;<span></span>
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<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
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<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_MilestonePayment', window );">Milestone Payment | $</a></td>
<td class="nump">$ 0<span></span>
</td>
<td class="nump">$ 600,000<span></span>
</td>
<td class="nump">$ 750,000<span></span>
</td>
<td class="nump">$ 600,000<span></span>
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<td class="pl " style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_us-gaap_OtherCommitmentsAxis=mrsn_LicenseAgreementsMember', window );">License agreements</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
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<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
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<td class="pl custom" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="top.Show.showAR( this, 'defref_mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty', window );">Number of biotechnology companies where Company has licensed intellectual property | company</a></td>
<td class="text">&#160;<span></span>
</td>
<td class="text">&#160;<span></span>
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<td class="nump">3<span></span>
</td>
<td class="text">&#160;<span></span>
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<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="top.Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>The cash outflow during the period for milestone payments under the terms of the agreement.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_MilestonePayment</td>
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<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Represents the number of biotechnology companies where Company has licensed intellectual property.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">mrsn_NumberOfBiotechnologyCompaniesWhereCompanyHasLicensedIntellectualProperty</td>
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<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">- Definition</a><div><p>Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="top.Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
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end
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<SEQUENCE>76
<FILENAME>Show.js
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
// Edgar(tm) Renderer was created by staff of the U.S. Securities and Exchange Commission.  Data and content created by government employees within the scope of their employment are not subject to domestic copyright protection. 17 U.S.C. 105.
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<TYPE>XML
<SEQUENCE>77
<FILENAME>report.css
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
/* Updated 2009-11-04 */
/* v2.2.0.24 */

/* DefRef Styles */
..report table.authRefData{
	background-color: #def;
	border: 2px solid #2F4497;
	font-size: 1em;
	position: absolute;
}

..report table.authRefData a {
	display: block;
	font-weight: bold;
}

..report table.authRefData p {
	margin-top: 0px;
}

..report table.authRefData .hide {
	background-color: #2F4497;
	padding: 1px 3px 0px 0px;
	text-align: right;
}

..report table.authRefData .hide a:hover {
	background-color: #2F4497;
}

..report table.authRefData .body {
	height: 150px;
	overflow: auto;
	width: 400px;
}

..report table.authRefData table{
	font-size: 1em;
}

/* Report Styles */
..pl a, .pl a:visited {
	color: black;
	text-decoration: none;
}

/* table */
..report {
	background-color: white;
	border: 2px solid #acf;
	clear: both;
	color: black;
	font: normal 8pt Helvetica, Arial, san-serif;
	margin-bottom: 2em;
}

..report hr {
	border: 1px solid #acf;
}

/* Top labels */
..report th {
	background-color: #acf;
	color: black;
	font-weight: bold;
	text-align: center;
}

..report th.void	{
	background-color: transparent;
	color: #000000;
	font: bold 10pt Helvetica, Arial, san-serif;
	text-align: left;
}

..report .pl {
	text-align: left;
	vertical-align: top;
	white-space: normal;
	width: 200px;
	white-space: normal; /* word-wrap: break-word; */
}

..report td.pl a.a {
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}

..report td.pl div.a {
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}

..report td.pl a:hover {
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}

/* Header rows... */
..report tr.rh {
	background-color: #acf;
	color: black;
	font-weight: bold;
}

/* Calendars... */
..report .rc {
	background-color: #f0f0f0;
}

/* Even rows... */
..report .re, .report .reu {
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}

..report .reu td {
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}

/* Odd rows... */
..report .ro, .report .rou {
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}

..report .rou td {
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}

..report .rou table td, .report .reu table td {
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}

/* styles for footnote marker */
..report .fn {
	white-space: nowrap;
}

/* styles for numeric types */
..report .num, .report .nump {
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	white-space: nowrap;
}

..report .nump {
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}

..report .nump {
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}

/* styles for text types */
..report .text {
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}

..report .text .big {
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	width: 17em;
}

..report .text .more {
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}

..report .text .note {
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}

..report .text .small {
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}

..report sup {
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}

..report .outerFootnotes {
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}
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>78
<FILENAME>FilingSummary.xml
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end
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
