CONDENSED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 394,585	$ 483,610
Marketable securities	37,713	43,332
Accounts receivable - trade, net	159,462	28,254
Accounts receivable from Sanofi	78,885	74,781
Prepaid expenses and other current assets	26,270	22,898
Total current assets	696,915	652,875
Restricted cash and marketable securities	8,154	7,721
Marketable securities	254,738	275,887
Property, plant, and equipment, at cost, net of accumulated depreciation and amortization	369,959	367,955
Other assets	20,393	19,145
Total assets	1,350,159	1,323,583
Current liabilities:
Accounts payable and accrued expenses	106,723	95,625
Deferred revenue from Sanofi, current portion	20,141	20,011
Deferred revenue - other, current portion	32,429	31,629
Facility lease obligations, current portion	1,093	1,006
Total current liabilities	160,386	148,271
Deferred revenue from Sanofi	83,625	86,017
Deferred revenue - other	154,929	162,593
Facility lease obligations	159,534	159,508
Convertible senior notes	280,206	275,019
Other long term liabilities	7,455	6,443
Total liabilities	846,135	837,851
Commitments and contingencies
Stockholders' equity:
Preferred stock
Common Stock	93	91
Additional paid-in capital	1,760,938	1,754,824
Accumulated deficit	(1,255,672)	(1,267,323)
Accumulated other comprehensive loss	(1,337)	(1,862)
Total stockholders' equity	504,024	485,732
Total liabilities and stockholders' equity	1,350,159	1,323,583
Class A Stock [Member]
Stockholders' equity:
Common Stock	$ 2	$ 2