Licensing and Other Arrangements - Zydus (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Mar. 03, 2020 USD ($) item	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Licensing and other arrangements
Revenue from contracts with customers		$ 200	$ 8,525	$ 753	$ 17,176
Zydus | License Agreement
Licensing and other arrangements
Maximum amount receivable milestone payments upon achievement of certain clinical development and regulatory approval events	$ 500
Maximum amount receivable upon achievement of commercial milestones	$ 23,500
Number of performance obligations | item	1
Contract assets		0		0
Contract liabilities		0		0
Capitalized contract costs		0		0
Revenue from contracts with customers		$ 0		$ 0