CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net revenues	$ 187,328	$ 167,492	$ 572,998	$ 511,349
Cost of net revenues	117,754	107,991	336,069	299,345
Gross profit	69,574	59,501	236,929	212,004
Operating expenses:
Technology and development	43,284	38,066	122,866	111,928
Sales and marketing	41,903	43,052	135,284	138,028
General and administrative	26,181	27,449	83,462	85,730
Total operating expenses	111,368	108,567	341,612	335,686
Loss from operations	(41,794)	(49,066)	(104,683)	(123,682)
Interest expense	(5,726)	(5,613)	(17,062)	(15,334)
Interest and other income, net	130	433	379	655
Loss before income taxes	(47,390)	(54,246)	(121,366)	(138,361)
Benefit from (provision for) income taxes	18,235	(8,831)	46,290	6,404
Net loss	$ (29,155)	$ (63,077)	$ (75,076)	$ (131,957)
Net loss per share - basic and diluted (in dollars per share)	$ (0.86)	$ (1.73)	$ (2.19)	$ (3.54)
Weighted-average shares outstanding - basic and diluted (in shares)	33,932	36,369	34,235	37,291
Cost of net revenues
Stock-based compensation	$ 1,131	$ 952	$ 3,436	$ 3,145
Technology and development
Stock-based compensation	2,725	2,443	5,696	7,744
Sales and marketing
Stock-based compensation	3,664	5,329	11,697	17,202
General and administrative
Stock-based compensation	$ 4,694	$ 7,032	$ 12,459	$ 21,740