Condensed Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Operating activities:
Net loss	$ (7,308)	$ (22,027)
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of warrants and other financial instruments	(2,219)	6,987
Depreciation	44	77
Amortization of license agreement	73	73
Stock-based compensation	550	650
Changes in operating assets and liabilities:
Restricted cash	55	65
Prepaid expenses and other current assets	62	232
Accounts payable, accrued expenses and other payables	(234)	(4,000)
Net cash used in operating activities	(8,977)	(17,943)
Investing activities:
Changes in other assets		40
Net cash provided by investing activities		40
Financing activities:
Proceeds from issuance of common stock, net of acquisition costs	17,019	10,380
Proceeds from exercise of employee stock plans		45
Net cash provided by financing activities	17,019	10,425
Increase (decrease) in cash and cash equivalents	8,042	(7,478)
Cash and cash equivalents at beginning of period	4,602	13,932
Cash and cash equivalents at end of period	12,644	6,454
Non- cash Disclosures:
Fair market value of stock issued in exchange for warrants	5,381
Fair market value reclassification of CEFF warrants to equity in connection with warrant exchange	3
Fair market value of private placement warrants at issuance		11,868
Fair market value reclassification of CEFF warrants to liabilities in connection with private placement		103
Fair market value of warrants at exercise		$ 5,043