STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Contract revenue	$ 14,688	$ 343	$ 325
Costs and expenses:
Cost of contract revenue	7,003
Research and development	17,885	28,032	25,780
General and administrative	11,379	10,805	11,928
Total costs and expenses	36,267	38,837	37,708
Loss from operations before other income (expense)	(21,579)	(38,494)	(37,383)
Other income (expense):
Interest income	136	189	285
Interest expense	(9)	(9)	(786)
Other income	26	485
Impairment of short-term investments			(1,338)
Realized gains on short-term investments			848
Change in fair value of warrant liability	2,474	1,671	(1,972)
Loss from operations before income tax	(18,952)	(36,158)	(40,346)
Income tax expense (benefit)	412	(450)
Net loss	$ (19,364)	$ (35,708)	$ (40,346)
Basic and diluted net loss per share:	$ (0.17)	$ (0.34)	$ (0.47)
Basic and diluted weighted average number of common shares outstanding	113,610	104,768	85,555