Revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue
Revenue accounted for under Topic 606				$ 28,895	$ 5,027	$ 9,481
Sinovant Sciences, LTD | License Agreement
Revenue
Regulatory milestone payment received					500
Merck & Co | License Agreement
Revenue
Revenue accounted for under Topic 606				1,200
Regulatory milestone payment received					1,800
Collaboration revenue
Revenue
Revenue accounted for under Topic 606				3,830	2,756	6,210
Collaboration revenue | Sumitomo Pharmaceuticals (Suzhou) | License Agreement
Revenue
Revenue accounted for under Topic 606				2,600
Collaboration revenue - Upfront payment
Revenue
Revenue accounted for under Topic 606				23,386	108	1,538
Collaboration revenue - Upfront payment | Sinovant Sciences, LTD | License Agreement
Revenue
Revenue accounted for under Topic 606						1,000
Collaboration revenue - Upfront payment | Sumitomo Pharmaceuticals (Suzhou) | License Agreement
Revenue
Revenue accounted for under Topic 606	$ 3,000	$ 1,000	$ 5,000
Collaboration revenue - Variable consideration | Sinovant Sciences, LTD | License Agreement
Revenue
Milestone payment received						5,000
Research premium and grant revenue
Revenue
Revenue accounted for under Topic 606				$ 1,679	$ 2,163	$ 1,733