Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended		114 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011
Revenue:
Research revenue	$ 2,380		$ 6,686		$ 37,794
Collaboration revenue	1,660		3,320		54,242
Total revenue	4,040		10,006		92,036
Operating Expenses:
Research and development	11,618	8,137	22,743	17,026	237,507
General and administrative	6,720	4,020	11,122	7,945	104,491
Restructuring charges					1,522
Impairment of leasehold improvements					1,030
Depreciation and amortization	426	529	864	1,066	9,342
In-process research and development					418
Total operating expenses	18,764	12,686	34,729	26,037	354,310
Loss from operations	(14,724)	(12,686)	(24,723)	(26,037)	(262,274)
Other income (expenses):
Interest income	46	35	105	88	14,018
Interest expense	(41)	(55)	(89)	(137)	(2,274)
Change in fair value of warrant liability	2,078	1,391	(1,354)	1,595	(3,218)
Other income			70		231
Loss before tax benefit	(12,641)	(11,315)	(25,991)	(24,491)	(253,517)
Benefit from income taxes					1,834
Net loss	(12,641)	(11,315)	(25,991)	(24,491)	(251,683)
Deemed dividend					(19,424)
Preferred stock accretion					(802)
Net loss attributable to common stockholders	$ (12,641)	$ (11,315)	$ (25,991)	$ (24,491)	$ (271,909)
Net loss attributable to common stockholders per common shares - basic and diluted	$ (0.37)	$ (0.41)	$ (0.75)	$ (0.94)
Weighted-average common shares outstanding - basic and diluted	34,530,693	27,623,297	34,514,947	25,956,366