CONDENSED CONSOLIDATED STATEMENT OF INCOME (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Net revenues	$ 116,708	$ 91,291
Cost of net revenues	61,853	50,053
Gross profit	54,855	41,238
Operating expenses:
Technology and development	24,027	18,508
Sales and marketing	34,895	27,038
General and administrative	19,897	14,772
Total operating expenses	78,819	60,318
Loss from operations	(23,964)	(19,080)
Interest expense	(139)	(152)
Interest and other income, net	7	7
Loss before income taxes	(24,096)	(19,225)
Benefit from income taxes	11,691	9,185
Net loss	$ (12,405)	$ (10,040)
Net loss per share - basic and diluted (in dollars per share)	$ (0.33)	$ (0.29)
Weighted-average shares outstanding - basic and diluted (in shares)	37,034	35,199