Condensed Consolidated Statement of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended		51 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011
Operating expenses:
Research and development expenses	$ (8,269)	$ (6,467)	$ (23,251)	$ (15,088)	$ (59,093)
General and administrative expenses	(5,905)	(2,821)	(17,267)	(6,169)	(30,481)
Depreciation and amortization expenses	(598)	(458)	(1,684)	(1,143)	(4,221)
Loss from operations	(14,772)	(9,746)	(42,202)	(22,400)	(93,795)
Other income (expense), net:
Interest income	2	20	2	22	172
Beneficial conversion feature expense related to convertible promissory note				(10,000)	(10,000)
Interest expense, net of amounts capitalized		(732)		(1,454)	(2,054)
Foreign currency gain (loss)	0		0	24	(435)
Loss from change in fair value of warrant liability		(159)	(6,914)	(2,449)	(9,279)
Other expense, net	2	(871)	(6,912)	(13,857)	(21,596)
Loss before income taxes	(14,770)	(10,617)	(49,114)	(36,257)	(115,391)
Income tax expenses - current					(47)
Net loss	(14,770)	(10,617)	(49,114)	(36,257)	(115,438)
Deemed dividend related to the beneficial conversion feature of Series C convertible preferred stock			(19,669)		(19,669)
Net loss attributable to stockholders	$ (14,770)	$ (10,617)	$ (68,783)	$ (36,257)	$ (135,107)
Weighted-average Class A and B common shares outstanding, basic and diluted	101,724	15,580	46,096	15,315
Class A Common Stock
Other income (expense), net:
Net loss per share of Class A and B common stock, basic and diluted	$ (0.15)		$ (0.73)
Class B Common Stock
Other income (expense), net:
Net loss per share of Class A and B common stock, basic and diluted	$ (0.15)	$ (0.13)	$ (0.73)	$ (0.51)