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Amount of financial support committed by investment company to investee that is discretionary.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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License Agreements - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	May 31, 2018
Research And Development Arrangement Contract To Perform For Others [Line Items]
Research and development expense	$ 15,198,000	$ 9,213,000	$ 28,223,000	$ 16,183,000
Commercial Agreements
Research And Development Arrangement Contract To Perform For Others [Line Items]
Funding provided for the research and development under the agreement in period			2020-02
Research and development expense			$ 300,000	$ 300,000
Commercial Agreements \| Clinical Stage Biopharmaceutical Company \| Maximum
Research And Development Arrangement Contract To Perform For Others [Line Items]
Contingent consideration additional common stock issued			666,670
Milestone payments			$ 70,300,000
Funding provided for the research and development under the agreement	2,000,000		2,000,000
Commercial Agreements \| Affiliate of Clinical-Stage Biopharmaceutical Company
Research And Development Arrangement Contract To Perform For Others [Line Items]
Aggregate purchase price			500,000
Additional amount invested					$ 500,000
Commercial Agreements And Compound Library And Option Agreement \| Clinical Stage Biopharmaceutical Company
Research And Development Arrangement Contract To Perform For Others [Line Items]
Contingent consideration liability	1,800,000		1,800,000
Other Licensing Agreements with Research Institutions
Research And Development Arrangement Contract To Perform For Others [Line Items]
Contingent consideration, milestone or royalty payments	$ 0		$ 0