Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities
Net loss	$ (190,481)	$ (111,178)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	1,526	1,002
Net (accretion) amortization on investment securities	(1,044)	250
Non-cash interest expense	6,685	5,095
Stock-based compensation expense	24,194	22,291
Remeasurement (gain) loss on embedded derivatives liabilities	(1,569)	666
Loss on assets disposal		26
Changes in operating assets and liabilities:
Inventories	(5,983)
Trade and other receivables, net	3,035
Unbilled - collaboration and license revenue	203
Prepaid research and development	(548)	3,812
Prepaid manufacturing	(15,547)	(6,167)
Prepaid expenses and other current assets	(2,837)	(3,483)
Prepaid and other long-term assets	9,595	(1,063)
Accounts payable	(2,993)	(2,765)
Accrued compensation and employee benefits	(4,063)	754
Accrued research and development	(5,958)	(1,768)
Accrued and other liabilities	3,453	1,342
Deferred revenue	2,499	(8,915)
Other long-term liabilities	(476)	(432)
Net cash used in operating activities	(180,309)	(100,533)
Investing activities
Purchases of property and equipment	(1,263)	(304)
Purchases of intangible assets		(5,000)
Purchases of investments	(166,944)	(186,407)
Proceeds from maturities of investments	236,775	170,529
Net cash provided by (used in) investing activities	68,568	(21,182)
Financing activities
Proceeds from debt issuance, net	95,000	48,000
Debt issuance costs paid		(557)
Proceeds from issuance of common stock pursuant to equity award plans	8,222	9,623
Dividends to Noncontrolling interest (SRX Cardio)'s shareholders	(140)
Net cash provided by financing activities	103,082	57,066
Net decrease in cash, cash equivalents and restricted cash	(8,659)	(64,649)
Cash, cash equivalents and restricted cash at beginning of period	181,741	188,658
Cash, cash equivalents and restricted cash at end of period	$ 173,082	$ 124,009