Condensed Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Operating activities:
Net loss	$ (2,772)us-gaap_NetIncomeLoss	$ (2,630)us-gaap_NetIncomeLoss
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	5us-gaap_Depreciation	4us-gaap_Depreciation
Amortization of license agreement		23us-gaap_AdjustmentForAmortization
Stock-based compensation	88us-gaap_ShareBasedCompensation	84us-gaap_ShareBasedCompensation
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(434)	(249)
Accounts payable and accrued expenses	(390)	144
Net cash used in operating activities	(3,503)	(2,624)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	9,207	10,860
Proceeds from exercise of warrants into common stock, net of issuance costs		9,494us-gaap_ProceedsFromWarrantExercises
Net cash provided by financing activities	9,207	20,354
Increase (decrease) in cash and cash equivalents	5,704	17,730
Cash at beginning of period	30,031us-gaap_Cash	7,005us-gaap_Cash
Cash at end of period	$ 35,735us-gaap_Cash	$ 24,735us-gaap_Cash

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of cash inflow (outflow) from operating activities, excluding discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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