License and Other Agreements - Revenue Participation Rights (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Aug. 31, 2020
License and other agreements
Non-cash interest expense on liability related to sale of future royalties		$ 11,955,000	$ 7,312,000	$ 31,950,000	$ 19,284,000
2018 RPI Funding Agreement
License and other agreements
Proceeds from royalty agreement	$ 100,000,000
Payments under funding agreement		$ 227,000	$ 0	$ 227,000	$ 0
2020 RPI Funding Agreement
License and other agreements
Sales-based participation rights sold, value						$ 250,000,000
Revenue Participation Right, tranche one | 2018 RPI Funding Agreement
License and other agreements
Participation rate for revenue participation right (percent)	2.10%
Revenue Participation Right, tranche one | 2018 RPI Funding Agreement | Maximum
License and other agreements
Annual global net sales threshold for revenue participation right	$ 1,500,000,000
Revenue Participation Right, tranche two | 2018 RPI Funding Agreement
License and other agreements
Participation rate for revenue participation right (percent)	1.50%