Collaborative Arrangements - In Licensing Agreements (Details) $ in Thousands				3 Months Ended		9 Months Ended
	Oct. 30, 2020 USD ($)	Jul. 17, 2020 USD ($) application	Jan. 13, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Aug. 22, 2020 USD ($)
Research and Development Arrangement, Contract to Perform for Others
Upfront payments				$ 66,500	$ 0	$ 109,500	$ 30,000
Milestone payments				1,000	0	6,000	0
Total				$ 67,500	$ 0	$ 115,500	$ 30,000
EUSA Pharma
Research and Development Arrangement, Contract to Perform for Others
Upfront payments			$ 40,000
Maximum milestone payments			$ 160,000
Assembly Biosciences, Inc.
Research and Development Arrangement, Contract to Perform for Others
Upfront payments		$ 40,000
Maximum milestone payments		$ 503,750
Candidates (candidates) | application		3
Bio-Thera Solutions, Ltd.
Research and Development Arrangement, Contract to Perform for Others
Maximum milestone payments								$ 145,000
Bio-Thera Solutions, Ltd. | Subsequent Event
Research and Development Arrangement, Contract to Perform for Others
Upfront payments	$ 20,000