CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities
Net loss	$ (105,952)	$ (55,996)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	14,880	8,707
Non-cash compensation expense	27,197	17,541
Other non-cash charges and expenses, net	832	1,623
Changes in assets and liabilities
Decrease (increase) in accounts receivable	8,548	(29,628)
(Increase) decrease in prepaid expenses and other assets	(8,158)	1,604
(Decrease) increase in deferred revenue	(20,554)	16,616
Increase in accounts payable, accrued expenses, and other liabilities	38,577	18,105
Total adjustments	61,322	34,568
Net cash used in operating activities	(44,630)	(21,428)
Cash flows from investing activities
Purchases of marketable securities	(15,638)	(222,168)
Sales or maturities of marketable securities	216,631	136,711
Capital expenditures	(37,030)	(45,324)
Increase in restricted cash	(681)	(1,800)
Net cash provided by (used in) investing activities	163,282	(132,581)
Cash flows from financing activities
Proceeds in connection with facility lease obligations	0	47,544
Payments in connection with facility lease obligations	(227)	(674)
Net proceeds from the issuance of Common Stock	23,752	12,064
Payments in connection with capital lease obligation	(437)	0
Net cash provided by financing activities	23,088	58,934
Net increase (decrease) in cash and cash equivalents	141,740	(95,075)
Cash and cash equivalents at beginning of period	112,572	207,075
Cash and cash equivalents at end of period	$ 254,312	$ 112,000