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, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) performanceObligation	Sep. 30, 2019 USD ($)
License, Collaboration and Other Revenue:
Recognized revenue	$ 59,988	$ 91,977	$ 238,608	$ 265,446
JT and Torii | Sublicense Agreement
License, Collaboration and Other Revenue:
Potential payment for achievement of annual net sales milestones			$ 55,000
License agreement, notice period for termination			6 months
Prior written notice for termination on the breach of agreement period			60 days
Number of performance obligations | performanceObligation			2
Recognized revenue	$ 1,200	$ 1,500	$ 4,000	$ 4,300