Condensed Consolidated Statements of Comprehensive Loss (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Aug. 31, 2012	Sep. 30, 2013	Aug. 31, 2012
Condensed Consolidated Statements Of Comprehensive Loss (Unaudited) [Abstract]
Net product sales	$ 6,603	$ 0	$ 6,624	$ 0
Operating expenses:
Cost of sales	442	0	867	0
Research and development	6,791	6,436	21,418	16,427
Selling, general and administrative	8,334	5,830	25,576	12,387
Total operating expenses	15,567	12,266	47,861	28,814
Loss from operations	(8,964)	(12,266)	(41,237)	(28,814)
Interest income	3	78	174	276
Interest expense	(2,287)	(1)	(4,088)	(2)
Foreign currency transaction gain/ (loss)	15	23	(20)	86
Realized gain/ (loss) on short-term investments	0	215	(129)	215
Unrealized gain/ (loss) on short-term investments	0	(143)	0	33
Adjustment to fair value of common stock warrants	(6,044)	1,872	(12,025)	995
Net loss	(17,277)	(10,222)	(57,325)	(27,211)
Other comprehensive gain (loss):
Foreign currency translation adjustment	11	(34)	(78)	(43)
Comprehensive loss	$ (17,266)	$ (10,256)	$ (57,403)	$ (27,254)
Net loss per share:
Basic and diluted (in dollars per share)	$ (0.29)	$ (0.21)	$ (1.01)	$ (0.56)
Weighted-average shares outstanding used to compute:
Basic and diluted (in shares)	59,964	49,766	56,658	48,899