Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net loss	$ (146,573)	$ (190,481)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	1,557	1,526
Amortization of right-of-use asset	1,081
Accretion of discount on investment securities	(634)	(1,044)
Non-cash interest expense	15,019	6,685
Stock-based compensation expense, net of capitalized labor	30,147	24,194
Remeasurement gain on embedded derivatives liabilities	(2,902)	(1,569)
Provision for excess and obsolete inventories	3,820
Loss on impairment of intangibles	3,151
Others	67
Changes in operating assets and liabilities:
Inventories	2,864	(5,983)
Trade and other receivables, net	(8,106)	3,035
Unbilled - collaboration and license revenue	5,085	203
Prepaid expenses and other current assets	2,304	(18,932)
Inventories, noncurrent portion	(21,963)
Prepaid and other long-term assets	2,897	9,595
Accounts payable	(3,307)	(2,993)
Accrued research and development	(1,432)	(5,958)
Accrued and other liabilities	4,833	(610)
Deferred revenue	(653)	2,499
Notes payable, long term royalty-based debt and long-term obligation to collaborator	(4,955)
Other long-term liabilities		(476)
Net cash used in operating activities	(117,700)	(180,309)
Investing activities
Capital expenditures, net	(791)	(1,263)
Purchases of investments	(76,778)	(166,944)
Proceeds from maturities of investments	167,158	236,775
Net cash provided by investing activities	89,589	68,568
Financing activities
Proceeds from debt issuance, net	59,203	95,000
Proceeds from issuance of common stock pursuant to equity award plans	16,603	8,222
Other		(140)
Net cash provided by financing activities	75,806	103,082
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(43)
Net (decrease) increase in cash, cash equivalents and restricted cash	47,652	(8,659)
Cash, cash equivalents and restricted cash at beginning of period	140,013	181,741
Cash, cash equivalents and restricted cash at end of period	$ 187,665	$ 173,082