Liabilities Related to Sales of Future Royalties - Activity Within the Liability Account (Details) - USD ($) $ in Thousands	3 Months Ended		123 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Dec. 31, 2021
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty monetization proceeds			$ 274,000
Non-cash royalty revenue	$ 17,561	$ 18,798	(351,012)
Non-cash interest expense	7,529	$ 13,296	251,802
Payments to RPI			(10,000)
Loss on revaluation of liability related to the sale of future royalties			23,522
Liabilities related to the sales of future royalties – ending balance	188,312		188,312
Less: unamortized transaction costs	(2,708)		(2,708)
Liabilities related to the sales of future royalties, net	185,604		185,604	$ 195,427
2012 Purchase and Sale Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty monetization proceeds			124,000
Non-cash royalty revenue			(289,655)
Non-cash interest expense			226,506
Payments to RPI			(10,000)
Loss on revaluation of liability related to the sale of future royalties			23,522
Liabilities related to the sales of future royalties – ending balance	74,373		74,373
Less: unamortized transaction costs	0		0
Liabilities related to the sales of future royalties, net	74,373		74,373
2020 Purchase and Sale Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty monetization proceeds			150,000
Non-cash royalty revenue			(61,357)
Non-cash interest expense			25,296
Payments to RPI			0
Loss on revaluation of liability related to the sale of future royalties			0
Liabilities related to the sales of future royalties – ending balance	113,939		113,939
Less: unamortized transaction costs	(2,708)		(2,708)
Liabilities related to the sales of future royalties, net	$ 111,231		$ 111,231