CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended		99 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011
Product revenue	$ 109	$ 85	$ 338	$ 127	$ 4,000
Service revenue	273		644		644
Grant revenue	427	576	1,009	1,103	6,319
Total revenue	809	661	1,991	1,230	10,963
Costs and expenses
Cost of product revenue	33	104	131	176	2,093
Research and development	982	4,216	2,135	8,262	110,798
Selling, general and administrative	1,410	2,693	2,392	6,765	73,334
Impairment of long-lived assets					1,894
Total costs and expenses	2,425	7,013	4,658	15,203	188,119
Operating loss	(1,616)	(6,352)	(2,667)	(13,973)	(177,156)
Interest income		4		16	4,153
Interest expense	(196)	(162)	(393)	(345)	(4,899)
Change in fair value of warrant liability	41	1,796	(15)	3,248	6,062
Other income			900		1,372
Net loss	(1,771)	(4,714)	(2,175)	(11,054)	(170,468)
Beneficial conversion feature related to Series B redeemable convertible preferred stock					(18,140)
Net loss attributable to common stockholders	$ (1,771)	$ (4,714)	$ (2,175)	$ (11,054)	$ (188,608)
Net loss attributable to common stockholders per share-basic (in dollars per share)	$ (0.02)	$ (0.06)	$ (0.03)	$ (0.14)
Net loss attributable to common stockholders per share-diluted (in dollars per share)	$ (0.02)	$ (0.06)	$ (0.03)	$ (0.14)
Weighted average number of common shares used in computation-basic (in shares)	85,350,069	79,859,226	85,231,836	79,561,205
Weighted average number of common shares used in computation-diluted (in shares)	85,350,069	79,859,226	85,231,836	79,561,205