Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Collaboration revenue	$ 60,027	$ 64,798	$ 176,330	$ 144,535
Operating expenses:
Research and development expenses	28,737	32,045	81,850	73,625
Selling, general and administrative expenses	39,288	32,345	124,746	70,369
Total operating expenses	68,025	64,390	206,596	143,994
Income (loss) from operations	(7,998)	408	(30,266)	541
Other income (expense), net:
Interest expense	(5,165)	(4,840)	(15,035)	(10,113)
Interest income	40	57	166	140
Other expense, net	(132)	(154)	(123)	(169)
Total other income (expense), net	(5,257)	(4,937)	(14,992)	(10,142)
Net loss before income tax (expense) benefit	(13,255)	(4,529)	(45,258)	(9,601)
Income tax (expense) benefit	(58)	(8)	(123)	4
Net loss	$ (13,313)	$ (4,537)	$ (45,381)	$ (9,597)
Basic and diluted net loss per common share	$ (0.18)	$ (0.06)	$ (0.60)	$ (0.13)
Weighted average common shares used in the calculation of basic and diluted net loss per common share	75,255	73,697	75,032	72,794