Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net loss	$ (78,096)	$ (84,510)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	792	756
Amortization of right-of-use asset	459
Accretion of discount on investment securities	(262)	(491)
Non-cash interest expense	6,481	2,581
Stock-based compensation expense, net of capitalized labor	17,894	10,980
Remeasurement gain on embedded derivatives liabilities	(472)	(1,634)
Provision for excess and obsolete inventories	3,945
Changes in operating assets and liabilities:
Inventories	1,498	(2,149)
Trade and other receivables, net	(5,938)	4,763
Unbilled - collaboration and license revenue	3,563	2,034
Prepaid expenses and other current assets	1,986	(11,244)
Prepaid and other long-term assets	(11,042)	4,797
Accounts payable	(4,489)	11,469
Accrued research and development	(1,455)	(22,868)
Accrued and other liabilities	3,225	(4,324)
Deferred revenue	303	1,650
Notes payable, long term royalty-based debt and long term obligation to collaborator	(2,027)
Other long-term liabilities		(230)
Net cash used in operating activities	(63,635)	(88,420)
Investing activities
Capital expenditures, net	(327)	(512)
Purchases of investments	(41,708)	(78,048)
Proceeds from maturities of investments	124,138	148,141
Net cash provided by investing activities	82,103	69,581
Financing activities
Proceeds from debt issuance, net	59,203
Proceeds from issuance of common stock pursuant to equity award plans, net	10,637	5,678
Other		(119)
Net cash provided by financing activities	69,840	5,559
Net (decrease) increase in cash, cash equivalents and restricted cash	88,308	(13,280)
Cash, cash equivalents and restricted cash at beginning of period	140,013	181,741
Cash, cash equivalents and restricted cash at end of period	$ 228,321	$ 168,461