Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (138,651)	$ (119,632)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to sale of future royalties	(9,895)	(8,230)
Non-cash interest expense on liability related to sale of future royalties	6,968	6,065
Stock-based compensation	25,236	25,385
Depreciation and amortization	4,502	3,077
Impairment of advance payments to contract manufacturers and equipment for terminated program	20,351	0
Accretion of premiums (discounts), net and other non-cash transactions	(1,289)	(3,183)
Changes in operating assets and liabilities:
Accounts receivable	(5,229)	319
Inventory	(1,655)	(397)
Operating leases, net	2,940	1,168
Other assets	1,067	4,209
Accounts payable	2,687	5,156
Accrued compensation	9,920	8,434
Other accrued expenses	7,716	774
Deferred revenue	(2,510)	(4,204)
Other liabilities	(233)	164
Net cash used in operating activities	(78,075)	(80,895)
Cash flows from investing activities:
Purchases of investments	(241,068)	(368,739)
Maturities of investments	439,735	362,249
Purchases of property, plant and equipment	(900)	(5,648)
Net cash provided by (used in) investing activities	197,767	(12,138)
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	11,077	4,894
Net cash provided by financing activities	11,077	4,894
Effect of foreign exchange rates on cash and cash equivalents	(97)	(14)
Net increase (decrease) in cash and cash equivalents	130,672	(88,153)
Cash and cash equivalents at beginning of period	96,363	194,905
Cash and cash equivalents at end of period	227,035	106,752
Supplemental disclosures of cash flow information:
Cash paid for interest	4,951	4,805
Operating lease right-of-use asset recognized in exchange for lease liabilities	$ 2,133	$ 1,289