CONSOLIDATED 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
License and collaboration revenue (Note 2)	$ 25,189	$ 174,460	$ 8,302
Service revenue	111	4,520
Total revenue	25,300	178,980	8,302
Operating expenses:
Research and development	77,743	57,985	63,447
General and administrative	24,380	16,095	16,888
Total operating expenses	102,123	74,080	80,335
Income (loss) from operations	(76,823)	104,900	(72,033)
Other income (expense):
Interest income	167	86	116
Interest expense	(232)	(206)	(287)
Revaluation of warrant liability	(46,715)	(19,532)	(7,804)
Other income (expense), net	(46,780)	(19,652)	(7,975)
Net income (loss)	$ (123,603)	$ 85,248	$ (80,008)
Net income (loss) per share - basic	$ (0.93)	$ 0.75	$ (0.86)
- diluted	$ (0.93)	$ 0.74	$ (0.86)
Weighted-average number of shares of common stock outstanding - basic	132,375	113,020	93,330
- diluted	132,375	114,734	93,330