Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
License and collaboration revenue	$ 66	$ 25,084	$ 448	$ 25,122
Service Revenue	19	17	36	100
Total revenue	85	25,101	484	25,222
Operating expenses:
Research and development	38,822	19,692	107,021	53,020
General and administrative	14,482	6,329	37,994	17,334
Total operating expenses	53,304	26,021	145,015	70,354
Loss from operations	(53,219)	(920)	(144,531)	(45,132)
Other income (expense):
Interest income	53	33	190	132
Interest expense	(47)	(49)	(154)	(172)
Revaluation of warrant liability		14,846	(15,924)	(26,629)
Other income (expense), net	6	14,830	(15,888)	(26,669)
Net income (loss)	$ (53,213)	$ 13,910	$ (160,419)	$ (71,801)
Net income (loss) per share - basic	$ (0.32)	$ 0.10	$ (0.98)	$ (0.55)
Net income (loss) per share - diluted	$ (0.32)	$ 0.10	$ (0.98)	$ (0.55)
Weighted-average number of shares of common stock outstanding - basic	166,296	132,587	164,378	131,215
Weighted-average number of shares of common stock outstanding - diluted	166,296	137,480	164,378	131,215