Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net loss	$ (37,672)	$ (54,218)	$ (57,394)
Adjustments to reconcile net loss to net cash flows from operating activities
Depreciation	329	123	207
Accretion of debt discount and loan costs	500	642	164
Amortization of intangible assets	970	972	1,140
Derivative loss (gain)		13,167	(121)
Impairment loss on assets		295
Stock-based compensation expense	14,249	6,883	3,327
Purchase of Arcion license with common stock			2,072
Changes in assets and liabilities:
Accounts receivable	653	(347)	(2,273)
Inventories	(730)	(1,828)
Prepaid expenses and other assets	(1,365)	(2,252)	(68)
Accounts payable and accrued expenses	5,072	4,325	(656)
Deferred revenue	14,262	3,405	(6,500)
Net cash flows from operating activities	(3,732)	(28,833)	(60,102)
Investing activities:
Purchase of equipment	(701)	(1,603)	(77)
Net cash flows from investing activities	(701)	(1,603)	(77)
Financing activities:
Proceeds from sales of securities, net of costs incurred	(40)	72,662
Proceeds from exercise of stock options	755	4,580	357
Proceeds from exercise of common stock warrants	1	7,741	50
Payment on note payable	(3,335)	(7,333)
Proceeds from notes payable	20,667		20,000
Return of short swing profits	6	82
Payment of deferred financing fees	(533)		(241)
Net cash flows from financing activities	17,521	77,732	20,166
Net change in cash and cash equivalents	13,088	47,296	(40,013)
Cash and cash equivalents at beginning of year	70,472	23,176	63,189
Cash and cash equivalents at end of year	83,560	70,472	23,176
Cash paid for interest	$ 1,885	$ 1,386	742
Cash paid for taxes			$ 80