CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (35,029)	$ (25,432)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	964	835
Stock-based compensation	3,862	3,179
Changes in valuation of warrant liability		(3,589)
Non-cash interest expense	603	139
Deferred income taxes	18	7
Non-cash tax expense (benefit) from other unrealized loss on available-for-sale securities	1,702	(2,085)
Changes in operating assets and liabilities:
Accounts receivable	645	69
Inventories	(1,318)	1,112
Other assets	435	739
Accounts payable	1,902	(4,176)
Accrued liabilities	(458)	(1,538)
Manufacturing and development obligations	(1,082)
Deferred revenue	189	256
Net cash used in operating activities	(27,567)	(30,484)
Investing activities
Capital expenditures	(118)	(325)
Purchases of investments	(70,560)	(69,983)
Proceeds from maturities of investments	19,500	22,444
Restricted cash	37	(114)
Net cash used in investing activities	(51,141)	(47,978)
Financing activities
Net proceeds from equity incentives and warrants	907	5,472
Net proceeds from public offering	14,547	75,324
Proceeds from loans		10,000
Repayment of debt	(60)	(56)
Net cash provided by financing activities	15,394	90,740
Net (decrease) increase in cash and cash equivalents	(63,314)	12,278
Cash and cash equivalents, beginning of period	71,018	22,781
Cash and cash equivalents, end of period	$ 7,704	$ 35,059