Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows From Operating Activities:
Net Loss	$ (7,373)	$ (16,842)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,006	1,959
Change in fair value of warrant liabilities	(7,249)	(3,015)
Depreciation	116	57
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	975	3,745
Deposits and other assets	(1)	(11)
Accounts payable	(270)	143
Accrued expenses	(877)	1,543
Accrued employee benefits	896	897
Deferred rent	29	(10)
Net Cash Used In Operating Activities	(11,748)	(11,534)
Cash Flows From Investing Activity:
Purchases of property and equipment	(11)	(45)
Net Cash Used In Investing Activity	(11)	(45)
Cash Flows From Financing Activities:
Proceeds from issuance of common stock for stock option exercises	166	810
Proceeds from “at the market” stock issuance	5,914	0
Net Cash Provided By Financing Activities	6,080	810
Net decrease in cash	(5,679)	(10,769)
Cash at beginning of period	19,055	20,818
Cash at end of period	13,376	10,049
Supplemental disclosures of cash flow information:
Cash paid for interest	0	0
Cash paid for taxes	$ 0	$ 0