Income Taxes - Schedule of Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 564,712	$ 456,284
Research and other credits	139,996	132,994
Operating lease liabilities	34,680	35,672
Stock-based compensation	33,408	32,517
Liability related to the sale of future royalties	23,757	32,737
Development derivative liability	6,639	0
Other	10,651	11,688
Deferred tax assets before valuation allowance	813,843	701,892
Valuation allowance for deferred tax assets	(785,748)	(670,103)
Total deferred tax assets	28,095	31,789
Deferred tax liabilities:
Operating lease right-of-use assets	(27,204)	(29,707)
Other	(564)	(1,856)
Total deferred tax liabilities	(27,768)	(31,563)
Net deferred tax assets	$ 327	$ 226