BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets
Cash and cash equivalents	$ 483,610	$ 112,572
Marketable securities	43,332	136,796
Accounts receivable from Sanofi	74,781	79,603
Accounts receivable - trade, net	28,254	2,314
Prepaid expenses and other current assets	22,898	26,337
Total current assets	652,875	357,622
Restricted cash and marketable securities	7,721	7,518
Marketable securities	275,887	370,053
Property, plant, and equipment, at cost, net of accumulated depreciation and amortization	367,955	347,450
Other assets	19,145	6,789
Total assets	1,323,583	1,089,432
Current liabilities
Accounts payable and accrued expenses	95,625	53,658
Deferred revenue from Sanofi, current portion	20,011	19,506
Deferred revenue - other, current portion	31,629	35,217
Facility lease obligations, current portion	1,006	675
Total current liabilities	148,271	109,056
Deferred revenue from Sanofi	86,017	97,081
Deferred revenue - other	162,593	188,775
Facility lease obligations	159,508	159,355
Convertible senior notes	275,019	0
Other long term liabilities	6,443	7,350
Total liabilities	837,851	561,617
Commitments and contingencies (Note 12)
Stockholders' equity
Preferred stock	0	0
Common Stock	91	87
Additional paid-in capital	1,754,824	1,575,780
Accumulated deficit	(1,267,323)	(1,045,563)
Accumulated other comprehensive loss	(1,862)	(2,491)
Total stockholders' equity	485,732	527,815
Total liabilities and stockholders' equity	1,323,583	1,089,432
Class A Stock [Member]
Stockholders' equity
Common Stock	$ 2	$ 2