CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended		102 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011
Product revenue	$ 116	$ 214	$ 454	$ 341	$ 4,116
Service revenue	385		1,029		1,029
Grant revenue	224	422	1,233	1,525	6,543
Total revenue	725	636	2,716	1,866	11,688
Costs and expenses
Cost of product revenue	70	94	201	270	2,163
Research and development	490	4,945	2,625	13,207	111,288
Selling, general and administrative	785	2,347	3,177	9,112	74,119
Impairment of long-lived assets		1,894	0	1,894	1,894
Total costs and expenses	1,345	9,280	6,003	24,483	189,464
Operating loss	(620)	(8,644)	(3,287)	(22,617)	(177,776)
Interest income		1		18	4,153
Interest expense	(151)	(106)	(544)	(451)	(5,050)
Change in fair value of warrant liability	(27)	(130)	(42)	3,117	6,035
Other income	0		900		1,372
Net loss	(798)	(8,879)	(2,973)	(19,933)	(171,266)
Beneficial conversion feature related to Series B redeemable convertible preferred stock	0				(18,140)
Net loss attributable to common stockholders	$ (798)	$ (8,879)	$ (2,973)	$ (19,933)	$ (189,406)
Net loss attributable to common stockholders per share--basic and diluted (in dollars per share)	$ (0.01)	$ (0.11)	$ (0.03)	$ (0.25)
Weighted average number of common shares used in computation--basic (in shares)	85,418,524	79,459,909	85,503,181	78,193,483
Weighted average number of common shares used in computation--diluted (in shares)	85,418,524	79,459,909	85,503,181	78,193,483