License and Collaboration Agreements - Summary of Revenues (Details) - Gilead and Taiho - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Collaboration
License And Collaboration Agreements [Line Items]
License revenue	$ 9,461	$ 1,750	$ 18,922	$ 3,500
Collaboration and License
License And Collaboration Agreements [Line Items]
License revenue	$ 9,461	$ 1,750	$ 18,922	$ 3,500