CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 22,998	$ 14,048	$ 17,127
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	29,424	22,316	23,429
Amortization of intangible assets	20,685	12,136	2,543
Stock-based compensation, net of forfeitures	37,322	33,870	16,366
Gain on disposal of property and equipment	(861)	(301)	(345)
Deferred income taxes	54	(5,766)	2,021
Tax benefit from stock-based compensation	14,619	8,391	5,973
Excess tax benefits from stock-based compensation	(16,622)	(8,380)	(5,967)
Gain on auction rate securities Rights	0	0	(6,266)
Loss on auction rate securities	0	0	6,266
Changes in operating assets and liabilities:
Accounts receivable, net	(577)	(7,205)	688
Inventories	(1,306)	766	(558)
Prepaid expenses and other current assets	(1,399)	(5,667)	(2,402)
Other assets	212	(1,402)	2
Accounts payable	15,230	(16,458)	8,652
Accrued and other liabilities	26,610	12,255	5,817
Deferred revenue	5,739	1,870	1,128
Other non-current liabilities	(747)	2,775	1,687
Net cash provided by operating activities	151,381	63,248	76,161
Cash flows from investing activities:
Acquisition of business and intangibles, net of cash acquired	(57,212)	(133,705)	(5,981)
Purchases of property and equipment	(40,535)	(23,149)	(14,405)
Capitalization of software and website development costs	(12,528)	(10,050)	(7,405)
Proceeds from sale of equipment	986	676	2,476
Proceeds from the sale of auction rate securities	0	0	47,925
Net cash provided by (used in) investing activities	(109,289)	(166,228)	22,610
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	10,211	22,277	14,703
Repurchases of common stock	(3,752)	0	0
Excess tax benefits from stock-based compensation	16,622	8,380	5,967
Principal payments of capital lease obligations	0	(6)	(9)
Net cash provided by financing activities	23,081	30,651	20,661
Net increase (decrease) in cash and cash equivalents	65,173	(72,329)	119,432
Cash and cash equivalents, beginning of period	179,915	252,244	132,812
Cash and cash equivalents, end of period	245,088	179,915	252,244
Cash paid during the period for:
Interest	0	0	1
Income taxes	618	140	663
Supplemental schedule of non-cash investing activities:
Net increase in accrued purchases of property and equipment	7,694	412	556
Estimated fair market value of building under build-to-suit lease	6,372	0	0
Amount due for acquisition of business	$ 963	$ 0	$ 0