Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (218,651,000)	$ (229,918,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to sale of future royalties	(17,579,000)	(17,321,000)
Non-cash interest expense on liability related to sale of future royalties	13,659,000	12,040,000
Stock-based compensation	48,607,000	49,907,000
Depreciation and amortization	7,692,000	6,132,000
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	(782,000)	(6,329,000)
Changes in operating assets and liabilities:
Accounts receivable	(10,443,000)	5,914,000
Inventory	81,000	(1,807,000)
Operating leases, net	4,245,000	8,415,000
Other assets	(27,214,000)	15,818,000
Accounts payable	425,000	3,480,000
Accrued compensation	12,469,000	9,773,000
Other accrued expenses	8,952,000	15,794,000
Deferred revenue	(3,790,000)	(6,715,000)
Net cash used in operating activities	(161,978,000)	(134,817,000)
Cash flows from investing activities:
Purchases of investments	(543,631,000)	(603,702,000)
Maturities of investments	860,330,000	634,145,000
Sales of investments	41,700,000	0
Purchases of property, plant and equipment	(3,594,000)	(17,291,000)
Net cash provided by investing activities	354,805,000	13,152,000
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	19,120,000	12,200,000
Repayment of senior notes	(250,000,000)	0
Net cash provided by (used in) financing activities	(230,880,000)	12,200,000
Effect of foreign exchange rates on cash and cash equivalents	(104,000)	(16,000)
Net decrease in cash and cash equivalents	(38,157,000)	(109,481,000)
Cash and cash equivalents at beginning of period	96,363,000	194,905,000
Cash and cash equivalents at end of period	58,206,000	85,424,000
Supplemental disclosures of cash flow information:
Cash paid for interest	9,742,000	9,455,000
Operating lease right-of-use asset recognized in exchange for lease liabilities	$ 2,133,000	$ 1,289,000