Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (17,157)	$ (23,550)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	331	328
Amortization of debt discount and debt issuance costs	318	0
Stock-based compensation expense	2,833	6,497
Non-cash interest expense	0	2,887
Disposals of property and equipment	0	4
Issuance of common stock to consultant	280	0
Derivative liability instrument expense	128	558
Warrant amendment expense	0	3,145
Interest amortization	0	45
Decrease in long term grants payable	(469)	(52)
Changes in operating assets and liabilities:
(Increase) decrease in other current assets	(160)	38
Increase in security deposit	(177)	(21)
Increase (decrease) in accounts payable	1,447	(3,895)
Increase (decrease) in accrued expenses	(1,250)	591
Decrease in due to related parties	(30)	(439)
Net cash used in operating activities	(13,906)	(13,864)
Cash flows from investing activities:
Change in restricted cash	(10)	140
Purchase of property and equipment	(167)	(23)
Net cash provided by (used in) investing activities	(177)	117
Cash flows from financing activities:
Proceeds received from issuance of shares, net of original issuance costs	0	11,029
Proceeds from Series D Preferred Stock	12,000	0
Proceeds received from exercise of options and warrants	143	251
Proceeds from issuance of debt	4,500	0
Proceeds received from sale of convertible note	0	1,000
Proceeds received from March 2014 financing	0	10,171
Repayment of loans	(3,191)	(1,486)
Payment of financing fees	(1,593)	0
Decrease in deposits for future financing	0	(500)
Net cash provided by financing activities	11,859	20,465
Net increase (decrease) in cash	(2,224)	6,718
Cash and cash equivalents at beginning of year	6,767	49
Cash at end of year	4,543	6,767
Supplemental disclosure of cash flow information:
Cash paid for interest	378	505
Cash paid for income taxes	0	0
Supplemental disclosure of non-cash financing activities:
Deemed dividend	6,959	616
Warrants issued to Series D Preferred Stock placement agents	758	0
Warrants issued to July 2015 debt financing placement agent	416	0
Series D Preferred Stock original issue discount	632	0
Shares issued to settle liabilities	537	0
Shares issued for financing costs	100	0
Dividend on Series C Preferred stock settled in common stock	0	129
Conversion of Series C Preferred Stock reclassified from mezzanine to equity	821	1,209
Reclassification of Series C Preferred Stock from mezzanine to equity	0	1,887
Reclassification of warrants from liability to equity	0	10,202
Intangible assets acquired with note payable	0	111
Accrued dividends on Series C Preferred Stock	0	256
Offset of debt in March 2014 financing (See Note 15)	0	329
Conversion of promissory note	0	1,000
Non-cash warrants with common stock	0	1,396
June warrants issued for Series C Preferred Stock amendment	$ 0	$ 441