Condensed Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Operating activities:
Net loss	$ (6,404)	$ (7,308)
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of warrants	(5)	(2,219)
Depreciation	12	44
Amortization of license agreement	74	73
Stock-based compensation	429	550
Changes in operating assets and liabilities:
Restricted cash		55
Prepaid expenses and other current assets	(41)	62
Accounts payable and accrued expenses	(1,003)	(234)
Net cash used in operating activities	(6,938)	(8,977)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	3,269	17,019
Net cash provided by financing activities	3,269	17,019
Increase (decrease) in cash and cash equivalents	(3,669)	8,042
Cash at beginning of period	9,972	4,602
Cash at end of period	6,303	12,644
Non-cash investing and financing activities:
Issuance of common stock in connection with the private placement warrant		5,381
Reclassification of CEFF warrants to equity from derivative liability due to exchange		$ 3