License, Collaboration and Other Significant Agreements - Sublicense Agreement with Japan Tobacco, Inc. and its subsidiary, Torii Pharmaceutical Co., Ltd. (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) performance_obligation	Sep. 30, 2020 USD ($)
License, Collaboration and Other Revenue:
Recognized revenue	$ 48,756	$ 59,988	$ 153,973	$ 238,608
JT and Torii | Sublicense Agreement
License, Collaboration and Other Revenue:
Number of performance obligations | performance_obligation			2
Recognized revenue	$ 1,400	$ 1,200	$ 4,100	$ 4,000