Condensed Consolidated Statements of Operations (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenue
Revenue from collaborative and licensing agreements		$ 4	$ 145	$ 9
Operating expenses
Research and development	4,193	2,862	8,381	5,469
General and administrative	1,633	1,860	3,462	4,691
Total operating expenses	5,826	4,722	11,843	10,160
Loss from operations	(5,826)	(4,718)	(11,698)	(10,151)
Other income (expense)
Investment and other income, net	51	12	364	52
Interest expense	(175)		(274)
Change in fair value of warrant liability	(28,023)	366	(29,481)	4,987
Total other income (expense), net	(28,147)	378	(29,391)	5,039
Net loss	$ (33,973)	$ (4,340)	$ (41,089)	$ (5,112)
Net loss per share - basic and diluted (in Dollars per share)	$ (0.91)	$ (0.17)	$ (1.22)	$ (0.20)
Shares used to compute basic and diluted net loss per share (in Shares)	37,433,822	25,753,405	33,781,593	25,753,405