CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (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]
Net product sales	$ 367,118	$ 249,172	$ 1,019,751	$ 576,622
Sanofi collaboration revenue	134,359	145,042	319,161	319,035
Bayer HealthCare collaboration revenue	88,583	26,701	134,594	48,308
Technology licensing	5,893	5,893	17,679	17,679
Other revenue	1,074	879	3,148	2,231
Total revenues	597,027	427,687	1,494,333	963,875
Expenses:
Research and development	224,045	158,295	591,807	444,530
Selling, general, and administrative	97,607	46,883	247,330	153,016
Cost of goods sold	28,253	20,145	83,557	54,286
Cost of collaboration manufacturing	10,320		23,684
Total expenses	360,225	225,323	946,378	651,832
Income from operations	236,802	202,364	547,955	312,043
Other income (expense):
Investment income	618	517	2,028	1,628
Interest expense	(11,736)	(11,413)	(34,776)	(33,809)
Total other income (expense)	(11,118)	(10,896)	(32,748)	(32,181)
Income before income taxes	225,684	191,468	515,207	279,862
Income tax expense	(84,378)		(187,651)
Net income	141,306	191,468	327,556	279,862
Net income per share - basic (in dollars per share)	$ 1.44	$ 2.02	$ 3.36	$ 2.97
Net income per share - diluted (in dollars per share)	$ 1.25	$ 1.72	$ 2.95	$ 2.55
Weighted average shares outstanding - basic (in shares)	98,226	95,012	97,602	94,349
Weighted average shares outstanding - diluted (in shares)	116,713	115,830	115,554	109,780
Statements of Comprehensive Income
Net income	141,306	191,468	327,556	279,862
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities, net of tax	578	467	(1,685)	(42)
Comprehensive income	$ 141,884	$ 191,935	$ 325,871	$ 279,820