CONDENSED CONSOLIDATED STATEMENT OF INCOME (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CONDENSED CONSOLIDATED STATEMENT OF INCOME (Unaudited) [Abstract]
Net revenues	$ 91,291	$ 57,229
Cost of net revenues	50,053	29,546
Gross profit	41,238	27,683
Operating expenses:
Technology and development	18,508	13,113
Sales and marketing	27,038	14,265
General and administrative	14,772	13,291
Total operating expenses	60,318	40,669
Loss from operations	(19,080)	(12,986)
Interest expense	(152)	0
Interest and other income, net	7	14
Loss before income taxes	(19,225)	(12,972)
Benefit from income taxes	9,185	5,212
Net loss	$ (10,040)	$ (7,760)
Net loss per share - basic and diluted (in dollars per share)	$ (0.29)	$ (0.27)
Weighted-average shares outstanding - basic and diluted (in shares)	35,199	28,674