Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (118,512,000)	$ (95,792,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash royalty revenue related to sale of future royalties	(8,230,000)	(6,920,000)
Non-cash interest expense on liability related to sale of future royalties	6,065,000	5,019,000
Stock-based compensation	25,385,000	19,949,000
Depreciation and amortization	3,077,000	2,541,000
Accretion of discounts, net and other non-cash transactions	(4,303,000)	(370,000)
Changes in operating assets and liabilities:
Accounts receivable	319,000	151,000
Inventory	(397,000)	51,000
Other assets	4,209,000	1,853,000
Accounts payable	5,156,000	6,492,000
Accrued compensation	8,434,000	6,867,000
Other accrued expenses	774,000	10,826,000
Deferred revenue	(4,204,000)	(3,678,000)
Other liabilities	1,332,000	545,000
Net cash used in operating activities	(80,895,000)	(52,466,000)
Cash flows from investing activities:
Purchases of investments	(368,739,000)
Maturities of investments	362,249,000	37,232,000
Sales of investments	0	11,963,000
Purchases of property, plant and equipment	(5,648,000)	(985,000)
Net cash provided by (used in) investing activities	(12,138,000)	48,210,000
Cash flows from financing activities:
Proceeds from shares issued under equity compensation plans	4,894,000	34,352,000
Net cash provided by financing activities	4,894,000	34,352,000
Effect of exchange rates on cash and cash equivalents	(14,000)	(53,000)
Net increase (decrease) in cash and cash equivalents	(88,153,000)	30,043,000
Cash and cash equivalents at beginning of period	194,905,000	4,762,000
Cash and cash equivalents at end of period	106,752,000	34,805,000
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 4,805,000	$ 4,952,000