CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Collaboration revenue	$ 70,149	$ 42,912	$ 116,303	$ 79,737
Operating expenses:
Research and development expenses	28,205	21,550	53,113	41,580
Selling, general and administrative expenses	41,890	22,337	85,458	38,024
Total operating expenses	70,095	43,887	138,571	79,604
Income (loss) from operations	54	(975)	(22,268)	133
Other income (expense), net:
Interest expense	(4,982)	(4,688)	(9,870)	(5,273)
Interest income	52	56	126	83
Other income (expense), net	10	83	9	(15)
Total other income (expense), net	(4,920)	(4,549)	(9,735)	(5,205)
Net loss before income tax (expense) benefit	(4,866)	(5,524)	(32,003)	(5,072)
Income tax (expense) benefit	(32)	24	(65)	12
Net loss	$ (4,898)	$ (5,500)	$ (32,068)	$ (5,060)
Basic and diluted net loss per common share	$ (0.07)	$ (0.08)	$ (0.43)	$ (0.07)
Weighted average common shares used in the calculation of basic and diluted net loss per common share	75,013	72,770	74,919	72,339