Condensed Consolidated Statements of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue:
External customers	$ 164,443	$ 144,957	$ 323,712	$ 279,365
Total revenue	164,443	144,957	323,712	279,365
Cost of services	43,642	34,926	83,628	69,482
Gross profit	120,801	110,031	240,084	209,883
Costs and expenses:
Sales and marketing	82,372	69,541	172,076	146,620
Technology and development	19,908	16,666	41,130	33,532
General and administrative	27,596	20,876	51,818	39,831
Amortization of acquired intangible assets	3,320	2,083	6,362	4,167
Total costs and expenses	133,196	109,166	271,386	224,150
Income (loss) from operations	(12,395)	865	(31,302)	(14,267)
Other income (expense):
Interest expense	(181)	(87)	(292)	(176)
Interest income	304	162	603	279
Other, net	(124)	(103)	(129)	(183)
Total other income (expense)	(1)	(28)	182	(80)
Income (loss) before income taxes	(12,396)	837	(31,120)	(14,347)
Income tax expense (benefit)	(4,830)	317	(12,328)	(5,709)
Net income (loss)	$ (7,566)	$ 520	$ (18,792)	$ (8,638)
Net income (loss) per share
Earnings per share, basic (in dollars per share)	$ (0.08)	$ 0.01	$ (0.20)	$ (0.09)
Earnings per share, diluted (in dollars per share)	$ (0.08)	$ 0.01	$ (0.20)	$ (0.09)
Weighted-average common shares outstanding used in computing net income (loss) per share:
Weighted average number of shares outstanding, basic (in shares)	92,385,195	94,592,297	93,566,920	94,314,192
Weighted average number of shares outstanding, diluted (in shares)	92,385,195	100,288,872	93,566,920	94,314,192
Consumer
Revenue:
External customers	$ 156,659	$ 138,329	$ 308,589	$ 266,530
Costs and expenses:
Income (loss) from operations	(8,279)	4,548	(21,756)	(6,208)
Enterprise
Revenue:
External customers	7,784	6,628	15,123	12,835
Costs and expenses:
Income (loss) from operations	$ (4,116)	$ (3,683)	$ (9,546)	$ (8,059)