CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Net product sales	$ 318,740	$ 127,931
Sanofi collaboration revenue	99,273	85,005
Bayer HealthCare collaboration revenue	14,907	12,483
Technology licensing	5,893	5,893
Other Revenue	851	477
Total revenues	439,664	231,789
Expenses:
Research and development	180,299	138,862
Selling, general, and administrative	77,260	58,428
Cost of goods sold	29,055	12,298
Total expenses	286,614	209,588
Income from operations	153,050	22,201
Other income (expense):
Investment income	456	610
Interest expense	(11,675)	(11,160)
Total other income (expense)	(11,219)	(10,550)
Income before income taxes	141,831	11,651
Income tax expense	(42,957)
Net income	98,874	11,651
Net income per share - basic (in dollars per share)	$ 1.02	$ 0.12
Net income per share - diluted (in dollars per share)	$ 0.90	$ 0.11
Weighted average shares outstanding - basic (in shares)	96,878	93,446
Weighted average shares outstanding - diluted (in shares)	109,369	107,734
Statements of Comprehensive Income
Net income	98,874	11,651
Other comprehensive (loss) income:
Unrealized (loss) gain on marketable securities, net of tax	(478)	525
Comprehensive income	$ 98,396	$ 12,176