Revenue (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Revenue
Revenue			$ 1,703	$ 7,551
Collaboration revenue
Revenue
Revenue			1,000	6,500
Collaboration revenue - upfront payment | License Agreement | Sinovant Sciences, LTD
Revenue
Revenue accounted for under Topic 606		$ 5,000		5,000
Collaboration revenue - upfront payment | License Agreement | Sunovion Pharmaceutics Canada, Inc.
Revenue
Revenue not accounted for under Topic 606	$ 1,000		1,000
Collaboration revenue - Variable consideration | Clinical trial application submission
Revenue
Revenue accounted for under Topic 606			1,500
Collaboration revenue - Variable consideration | License Agreement | Clinical trial application submission | Sinovant Sciences, LTD
Revenue
Revenue accounted for under Topic 606				1,500
Research premium
Revenue
Revenue			393	770
Government grants
Revenue
Revenue			$ 311	$ 281