Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Collaboration revenue	$ 943,258	$ 710,487	$ 272,942
Operating expenses:
Research and development expenses	232,100	189,570	118,952
Selling, general and administrative expenses	296,545	239,071	176,231
Total operating expenses	528,645	428,641	295,183
Income (loss) from operations	414,613	281,846	(22,241)
Other income (expense), net:
Loss on extinguishment of Convertible Notes	(21,087)
Interest expense	(12,483)	(21,690)	(20,249)
Other, net	275	38	(8)
Total other income (expense), net	(33,295)	(21,652)	(20,257)
Income (loss) before income tax (expense) benefit	381,318	260,194	(42,498)
Income tax (expense) benefit	(136,593)	16,258	(115)
Net income (loss)	$ 244,725	$ 276,452	$ (42,613)
Basic net income (loss) per common share	$ 1.53	$ 1.80	$ (0.28)
Diluted net income (loss) per common share	$ 1.47	$ 1.71	$ (0.28)
Weighted-average common shares used in the calculation of basic net income (loss) per common share	160,345	153,859	150,331
Weighted-average common shares used in the calculation of diluted net income (loss) per common share	169,324	170,001	150,331