Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (3,666)	$ (2,901)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	112	129
Warrant revaluation expense (income)	29	(235)
Derivative revaluation income	(55)	63
Depreciation and amortization of long lived assets	85	101
Decrease (increase) in operating assets:
Prepaid expenses and other current assets	(1,112)	0
Other assets	39	(12)
Increase (decrease) in operating liabilities:
Accounts payable	1,060	23
Related party payable	(47)	(1,929)
Accrued expenses, deferred rent	265	(190)
Accrued lease liabilities - operating lease	16	0
Accrued interest payable	197	190
Net cash used in operating activities	(3,077)	(4,761)
Cash flows from investing activities:
Purchase of property and equipment	(9)	(35)
Net cash used in investing activities	(9)	(35)
Cash flows from financing activities:
Payment of deferred offering costs	(22)	(444)
Proceeds from conversion of pre-funded warrants	0	24
Net cash provided by financing activities	(22)	(420)
Effect of exchange rate changes on cash balances	0	0
Net increase (decrease) in cash and cash equivalents	(3,108)	(5,216)
Cash and cash equivalents, beginning of period	14,430	17,417
Cash and cash equivalents, end of period	11,322	12,201
Supplemental disclosures of cash flow information:
Property and equipment in accounts payable	46	33
Offering costs in accounts payable and accrued expenses	15	0
Dividend paid in-kind to preferred stockholders	85	82
Deemed dividend on preferred stock	$ 140	$ 121