Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (327,237,000)	$ (328,503,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to sale of future royalties	(28,001,000)	(27,585,000)
Non-cash interest expense on liability related to sale of future royalties	22,084,000	17,853,000
Stock-based compensation	72,274,000	74,787,000
Depreciation and amortization	10,937,000	9,582,000
Impairment of advance payments to contract manufacturers and equipment for terminated program	20,351,000	0
Accretion of premiums (discounts), net and other non-cash transactions	1,150,000	(9,147,000)
Changes in operating assets and liabilities:
Accounts receivable	(6,123,000)	2,008,000
Inventory	(227,000)	(2,339,000)
Operating leases, net	4,316,000	11,550,000
Other assets	(5,588,000)	18,127,000
Accounts payable	(3,337,000)	16,109,000
Accrued compensation	20,478,000	13,164,000
Other accrued expenses	9,340,000	10,401,000
Deferred revenue	(5,070,000)	(9,465,000)
Net cash used in operating activities	(214,653,000)	(203,458,000)
Cash flows from investing activities:
Purchases of investments	(791,445,000)	(1,028,883,000)
Maturities of investments	1,158,722,000	1,122,902,000
Sales of investments	41,700,000	0
Purchases of property, plant and equipment	(5,504,000)	(22,614,000)
Net cash provided by investing activities	403,473,000	71,405,000
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	20,651,000	18,449,000
Repayment of senior notes	(250,000,000)	0
Net cash provided by (used in) financing activities	(229,349,000)	18,449,000
Effect of foreign exchange rates on cash and cash equivalents	9,000	(77,000)
Net decrease in cash and cash equivalents	(40,520,000)	(113,681,000)
Cash and cash equivalents at beginning of period	96,363,000	194,905,000
Cash and cash equivalents at end of period	55,843,000	81,224,000
Supplemental disclosures of cash flow information:
Cash paid for interest	9,742,000	14,299,000
Operating lease right-of-use asset recognized in exchange for lease liabilities	$ 2,133,000	$ 56,025,000