Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net loss	$ (19,025)	$ (9,499)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	63	1,125
Warrant revaluation expense (income)	9,723	(7,511)
Derivative revaluation income	(541)	0
Inventory reserve	0	151
Depreciation and amortization	184	391
Loss on disposal or impairment of property and equipment	40	3,970
Recovery of doubtful accounts	0	(12)
Decrease (increase) in operating assets:
Accounts receivable	0	12
Inventory	0	222
Prepaid expenses and other current assets	72	728
Other assets	(19)	(64)
Increase (decrease) in operating liabilities:
Accounts payable	192	(3)
Related party payable	736	(9,796)
Accrued expenses and deferred rent	(776)	(518)
Accrued interest payable	368	0
Deferred revenue	0	(49)
Net cash used in operating activities	(8,983)	(20,853)
Cash flows from investing activities:
Purchase of property and equipment	(243)	(143)
Net cash used in investing activities	(243)	(143)
Cash flows from financing activities:
Proceeds from 2017 Series A Preferred Stock Offering, (net of offering costs of $377)	7,623	0
Payment of deferred offering costs	0	(109)
Principal payments on capital lease obligations	0	(2)
Net cash provided by (used in) financing activities	7,623	(111)
Net decrease in cash and cash equivalents	(1,603)	(21,107)
Cash and cash equivalents, beginning of period	17,515	29,268
Cash and cash equivalents, end of period	15,912	8,161
Supplemental disclosures of cash flow information:
Property and equipment in accounts payable	26	46
Offering costs in accounts payable and accrued expenses	0	11
Reduction of warrant liability upon cashless exercise of warrants	41	0
Reduction in accrued interest payable upon cashless exercise of promissory notes	2	0
Dividend paid in-kind to preferred stockholders	100	0
Deemed dividend on preferred stock	$ 3,870	$ 0