Collaboration and License Agreements - Revenue Recognized - CStone (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Collaboration Agreements
Total CStone collaboration revenue	$ 8,343	$ 5,110	$ 14,510	$ 5,840
Collaboration | C Stone
Collaboration Agreements
License milestone revenue		4,000	2,000	4,000
Manufacturing services related to territory-specific activities	1,263	144	1,397	144
Total CStone collaboration revenue	$ 1,263	$ 4,144	$ 3,397	$ 4,144