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Strategic License Agreements - Narrative (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended			63 Months Ended
	Sep. 26, 2019	Oct. 24, 2014	Oct. 31, 2014	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Sep. 06, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent development milestone payment				$ 10,000			$ 10,000
Payment for contingent amounts				$ 20,000	$ 0	$ 0
Modis Acquisition
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Expiration period of license agreement following first bona fide sale of licensed product	15 years
Upon Achievement of Certain Commercial Milestone Events \| Modis Acquisition
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent payment under license agreement								$ 10,000
Upon Achievement of Certain Commercial Milestone Events \| Modis Acquisition \| Columbia University
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent payment under license agreement	$ 25,000
Upon Achievement of Research, Development and Regulatory Milestone \| Modis Acquisition
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent payment under license agreement								$ 3,000
Upon Achievement of Regulatory Milestones \| Modis Acquisition \| Columbia University
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent payment under license agreement	$ 2,900
Brabant Pharma Limited
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate amount of contingent liabilities			$ 95,000
Brabant Pharma Limited \| Regulatory Milestones
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate amount of contingent liabilities		$ 50,000	50,000
Payment for contingent amounts							$ 20,000
Brabant Pharma Limited \| Sales Milestones
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Aggregate amount of contingent liabilities			$ 45,000