CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net loss	$ (29,436)	$ (45,103)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	22,995	19,909
Amortization of intangible assets	6,119	7,684
Amortization of debt discount and transaction costs	3,532	3,340
Stock-based compensation	10,150	17,760
Loss on disposal of property and equipment	218	463
Deferred income taxes	3,637	1,539
Tax benefit from stock-based compensation	5,638	17,891
Excess tax benefits from stock-based compensation	(6,859)	(18,139)
Changes in operating assets and liabilities:
Accounts receivable	25,137	10,928
Inventories	1,457	1,012
Prepaid expenses and other assets	(26,607)	(28,492)
Accounts payable	(17,080)	(18,015)
Accrued and other liabilities	(82,824)	(78,508)
Net cash used in operating activities	(83,923)	(107,731)
Cash flows from investing activities:
Purchases of property and equipment	(10,131)	(11,059)
Capitalization of software and website development costs	(8,639)	(3,798)
Purchases of investments	(8,026)	(3,150)
Proceeds from the maturities of investments	11,615	11,700
Proceeds from sale of property and equipment	39	13
Net cash used in investing activities	(15,142)	(6,294)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of stock options	491	1,168
Repurchases of common stock	(47,461)	(45,195)
Excess tax benefits from stock-based compensation	6,859	18,139
Principal payments of capital lease and financing obligations	(3,772)	(2,466)
Net cash used in financing activities	(43,883)	(28,354)
Net decrease in cash and cash equivalents	(142,948)	(142,379)
Cash and cash equivalents, beginning of period	288,863	380,543
Cash and cash equivalents, end of period	145,915	238,164
Supplemental schedule of non-cash investing / financing activities:
Net increase (decrease) in accrued purchases of property and equipment	(4,634)	2,919
Net increase (decrease) in accrued capitalized software and website development costs	(471)	274
Stock-based compensation capitalized with software and website development costs	537	357
Increase in estimated fair market value of buildings under build-to-suit leases	0	8,459
Property and equipment acquired under capital leases	$ 0	$ 9,803