Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (248,486)	$ (218,651)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to sale of future royalties	(39,254)	(17,579)
Non-cash interest expense on liability related to sale of future royalties	26,385	13,659
Change in fair value of development derivative liability	4,312	0
Non-cash research and development expense	5,795	0
Stock-based compensation	47,612	48,607
Depreciation and amortization	7,090	7,692
Impairment of advance payments to contract manufacturers and equipment for terminated program	0	20,351
Amortization of premiums (discounts), net and other non-cash transactions	4,090	(782)
Changes in operating assets and liabilities:
Accounts receivable	10,018	(10,443)
Inventory	676	81
Operating leases, net	2,260	4,245
Other assets	11,585	(27,214)
Accounts payable	(2,101)	425
Accrued compensation	14,133	12,469
Other accrued expenses	(3,496)	8,952
Deferred revenue	(605)	(3,790)
Net cash used in operating activities	(159,986)	(161,978)
Cash flows from investing activities:
Purchases of investments	(527,887)	(543,631)
Maturities of investments	612,419	860,330
Sales of investments	5,035	41,700
Purchases of property, plant and equipment	(6,157)	(3,594)
Net cash provided by investing activities	83,410	354,805
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	28,523	19,120
Cash receipts from development derivative liability	1,500	0
Repayment of senior notes	0	(250,000)
Net cash provided by (used in) financing activities	30,023	(230,880)
Effect of foreign exchange rates on cash and cash equivalents	(57)	(104)
Net decrease in cash and cash equivalents	(46,610)	(38,157)
Cash and cash equivalents at beginning of period	198,955	96,363
Cash and cash equivalents at end of period	152,345	58,206
Supplemental disclosures of cash flow information:
Cash paid for interest	0	9,742
Operating lease right-of-use asset recognized in exchange for lease liabilities	$ 1,057	$ 2,133