CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Revenue	$ 43,229	$ 38,505	$ 85,725	$ 75,264
Operating expenses:
Cost of revenue	10,612	8,492	20,746	16,414
Product development	9,047	7,219	17,068	13,877
Sales and marketing	15,499	13,017	29,977	24,107
General and administrative	9,835	9,342	20,072	15,467
Amortization of intangibles	224	11	448	87
Total operating expenses	45,217	38,081	88,311	69,952
(Loss) income from operations	(1,988)	424	(2,586)	5,312
Other income:
Financial income	4	(254)	31	77
Interest income	16	21	24	36
Total other income, net	20	(233)	55	113
(Loss) income before (benefit from) provision for income taxes	(1,968)	191	(2,531)	5,425
(Benefit from) provision for income taxes	(138)	51	(470)	2,162
Net (loss) income	$ (1,830)	$ 140	$ (2,061)	$ 3,263
Basic net (loss) income per common share	$ (0.03)	$ 0.00	$ (0.04)	$ 0.06
Diluted net (loss) income per common share	$ (0.03)	$ 0.00	$ (0.04)	$ 0.06
Weighted average shares outstanding used in basic net (loss) income per common share calculation	54,806,694	55,146,901	55,332,449	54,786,499
Weighted average shares outstanding used in diluted net (loss) income per common share calculation	54,806,694	57,150,256	55,332,449	56,649,160