Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (5,795)	$ (19,025)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	260	63
Warrant revaluation expense (income)	(326)	9,723
Derivative revaluation income	(179)	(541)
Depreciation and amortization of long lived assets	202	184
Loss on disposal or impairment of property and equipment	0	40
Decrease (increase) in operating assets:
Prepaid expenses and other current assets	30	72
Other assets	0	(19)
Increase (decrease) in operating liabilities:
Accounts payable	51	192
Related party payable	(2,027)	736
Accrued expenses and deferred rent	(74)	(776)
Accrued interest payable	382	368
Net cash used in operating activities	(7,476)	(8,983)
Cash flows from investing activities:
Purchase of property and equipment	(83)	(243)
Net cash used in investing activities	(83)	(243)
Cash flows from financing activities:
Proceeds from 2017 Series A Preferred Stock Offering, (net of offering costs of $377)	0	7,623
Payment of deferred offering costs	(444)	0
Proceeds from conversion of pre-funded warrants	24	0
Proceeds from conversion of common warrants	499	0
Proceeds from May 2018 Registered Direct Offering, (net of offering costs of $527)	5,473	0
Net cash provided by financing activities	5,552	7,623
Effect of exchange rate changes on cash balances	0	0
Net increase (decrease) in cash and cash equivalents	(2,007)	(1,603)
Cash and cash equivalents, beginning of period	17,417	17,515
Cash and cash equivalents, end of period	15,410	15,912
Supplemental disclosures of cash flow information:
Property and equipment in accounts payable	52	26
Offering costs in accounts payable and accrued expenses	100	0
Reduction of warrant liability upon cashless exercise of warrants	0	41
Reduction in interest payable upon cashless exercise of promissory notes	0	2
Dividend paid in-kind to preferred stockholders	165	100
Deemed dividend on preferred stock	$ 247	$ 3,870