Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities:
Net loss	$ (6,096)	$ (6,559)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	10	8
Amortization of license agreement		46
Stock-based compensation	370	222
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(149)	(341)
Accounts payable and accrued expenses	(253)	697
Net cash used in operating activities	(6,118)	(5,927)
Investing activities:
Purchases of furniture, fixtures, equipment and other assets	(15)
Net cash used in investing activities	(15)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	9,195	25,681
Proceeds from exercise of warrants into common stock, net of issuance costs		9,512
Net cash provided by financing activities	9,195	35,193
Increase in cash	3,062	29,266
Cash at beginning of period	30,031	7,005
Cash at end of period	$ 33,093	$ 36,271