Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows From Operating Activities:
Net Loss	$ (2,326)	$ (3,058)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	676	1,135
Warrant issued to consultant	9	0
Change in fair value of warrant liabilities	(2,655)	(5,090)
Depreciation	71	57
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	221	(851)
Accounts payable	(527)	1,803
Accrued expenses	(468)	(493)
Accrued employee benefits	(1,058)	474
Deferred rent	(22)	15
Net Cash Used In Operating Activities	(6,079)	(6,008)
Cash Flows From Investing Activities:
Purchases of property and equipment	0	(11)
Net Cash Used In Investing Activities	0	(11)
Cash Flows From Financing Activities:
Proceeds from issuance of common stock for stock option exercises	0	166
Proceeds from "at the market" stock issuance	0	269
Net Cash Provided By Financing Activities	0	435
Net decrease in cash	(6,079)	(5,584)
Cash at beginning of period	17,116	19,055
Cash at end of period	$ 11,037	$ 13,471