Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
-Paragraph 22
-Subparagraph (b)
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Collaboration and Other Agreements - NIAID Contract (Details)		3 Months Ended		12 Months Ended
	Sep. 15, 2015 USD ($) Molecule	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Collaboration And Other Agreements [Line Items]
Revenues		$ 9,662,000	$ 4,695,000
NIAID
Collaboration And Other Agreements [Line Items]
Commercialization of molecules \| Molecule	2
Base period	$ 7,500,000
Additional development funding options under agreement	17,000,000.0
Total potential value	$ 24,500,000
Proceeds from additional development funding options under agreement				$ 10,800,000
Revenues From Grants \| NIAID
Collaboration And Other Agreements [Line Items]
Revenues		$ 200,000	$ 200,000