CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Revenue:
License revenue	$ 64
Service revenue	17	56
Total revenue	81	56
Operating expenses:
Research and development	28,774	14,574
General and administrative	11,288	4,854
Total operating expenses	40,062	19,428
Loss from operations	(39,981)	(19,372)
Other income (expense):
Interest income	68	55
Interest expense	(57)	(60)
Revaluation of warrant liability	(15,924)	(18,572)
Other income (expense), net	(15,913)	(18,577)
Net loss	$ (55,894)	$ (37,949)
Net loss per share - basic and diluted	$ (0.35)	$ (0.29)
Weighted-average number of shares of common stock outstanding - basic and diluted	160,970	128,998