Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash Flows From Operating Activities:
Net Loss	$ (18,304)	$ (25,331)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,906	2,906
Change in fair value of warrant liabilities	(2,157)	(3,681)
Depreciation	172	111
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,251	6,428
Deposits and other assets	0	(12)
Accounts payable	(895)	(171)
Accrued expenses	(557)	1,193
Accrued employee benefits	1,293	1,063
Deferred rent	19	(23)
Net Cash Used In Operating Activities	(16,272)	(17,517)
Cash Flows From Investing Activities:
Purchases of property and equipment	(209)	(199)
Net Cash Used In Investing Activities	(209)	(199)
Cash Flows From Financing Activities:
Proceeds from sale of Series A convertible preferred stock, net of issuance cost	11,952	0
Proceeds from issuance of common stock for stock option exercises	166	814
Proceeds from “at the market” stock issuance	6,358	633
Net Cash Provided By Financing Activities	18,476	1,447
Net increase (decrease) in cash	1,995	(16,269)
Cash at beginning of period	19,055	20,818
Cash at end of period	$ 21,050	$ 4,549