CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net loss	$ (10,040)	$ (7,760)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	6,011	5,114
Amortization of intangible assets	4,013	719
Stock-based compensation, net of forfeitures	9,617	5,235
Loss/(gain) on disposal of property and equipment	(402)	11
Deferred income taxes	(1,248)	(466)
Tax benefit from stock-based compensation	16,334	15,709
Excess tax benefits from stock-based compensation	(16,334)	(15,709)
Changes in operating assets and liabilities:
Accounts receivable, net	(381)	1,046
Inventories	27	811
Prepaid expenses and other current assets	(23,204)	(19,646)
Other assets	(2,253)	38
Accounts payable	(2,257)	(15,403)
Accrued and other liabilities	(28,916)	(22,072)
Deferred revenue	1,072	(476)
Net cash used in operating activities	(47,961)	(52,849)
Cash flows from investing activities:
Acquisition of intangible assets	0	(400)
Purchases of property and equipment	(5,037)	(3,572)
Capitalization of software and website development costs	(3,072)	(2,318)
Proceeds from sale of equipment	410	20
Net cash used in investing activities	(7,699)	(6,270)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	3,345	7,444
Excess tax benefits from stock-based compensation	16,334	15,709
Net cash provided by financing activities	19,679	23,153
Net decrease in cash and cash equivalents	(35,981)	(35,966)
Cash and cash equivalents, beginning of period	179,915	252,244
Cash and cash equivalents, end of period	143,934	216,278
Supplemental schedule of non-cash investing activities
Net increase in accrued purchases of property and equipment	$ 1,462	$ 1,874