CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Revenue		$ 58,241	$ 50,919
Costs and expenses
Cost of revenue	[1],[2],[3]	13,954	13,781
Sales and marketing	[2],[3]	24,131	21,700
General and administrative	[2],[3]	10,123	9,692
Product development	[2],[3]	13,252	9,958
Restructuring costs		178	240
Amortization of purchased intangibles		424	472
Total costs and expenses	[2],[3]	62,062	55,843
Loss from operations		(3,821)	(4,924)
Other income, net		129	320
Loss before (benefit from) provision for income taxes		(3,692)	(4,604)
(Benefit from) provision for income taxes		(489)	1,072
Net loss		$ (3,203)	$ (5,676)
Net loss per share of common stock:
Basic net loss per common share (in dollars per share)		$ (0.06)	$ (0.10)
Diluted net loss per common share (in dollars per share)		$ (0.06)	$ (0.10)
Weighted-average shares used to compute net loss per share:
Weighted average shares outstanding used in basic net loss per common share calculation (in shares)		57,309,707	55,975,093
Weighted average shares outstanding used in diluted net loss per common share calculation (in shares)		57,309,707	55,975,093
Cost of revenue [Member]
Additional Information on Operating Expenses
Stock-based compensation expense		$ 154	$ 75
Depreciation expense		1,916	1,765
Amortization of purchased intangibles		287	959
Sales and marketing [Member]
Additional Information on Operating Expenses
Stock-based compensation expense		886	654
Depreciation expense		356	381
General and administrative [Member]
Additional Information on Operating Expenses
Stock-based compensation expense		840	662
Depreciation expense		246	249
Product development [Member]
Additional Information on Operating Expenses
Stock-based compensation expense		558	522
Depreciation expense		$ 840	$ 398

[1] Amounts include amortization expense as follows: Cost of revenue $287 thousand and $959 thousand thousand for the three months ended March 31, 2018 and 2017, respectively.Amounts include amortization expense as follows: Cost of revenue and thousand for the three months ended March 31, 2018 and 2017, respectively.

[2] Amounts include depreciation expense as follows: Cost of revenue $1,916 thousand and $1,765 thousand for the three months ended March 31, 2018 and 2017, respectively, Sales and marketing $356 thousand and $381 thousand for the three months ended March 31, 2018 and 2017, respectively, General and administrative $246 thousand and $249 thousand for the three months ended March 31, 2018 and 2017, respectively, and Product development $840 thousand and $398 thousand for the three months ended March 31, 2018 and 2017, respectively. Amounts include depreciation expense as follows: Cost of revenue and $ for the three months ended March 31, 2018 and 2017, respectively, Sales and marketing $ and $ for the three months ended March 31, 2018 and 2017, respectively, General and administrative $ and $ for the three months ended March 31, 2018 and 2017, respectively, and Product development $ and $ for the three months ended March 31, 2018 and 2017, respectively.

[3] Amounts include stock compensation expense as follows: Cost of revenue $154 thousand and $75 thousand for the three months ended March 31, 2018 and 2017, respectively, Sales and marketing $886 thousand and $654 thousand for the three months ended March 31, 2018 and 2017, respectively, General and administrative $840 thousand and $662 thousand for the three months ended March 31, 2018 and 2017, respectively and Product development $558 thousand and $522 thousand for the three months ended March 31, 2018 and 2017, respectively. Amounts include stock compensation expense as follows: Cost of revenue $301 thousand and $342 thousand for the three months ended March 31, 2018 and 2017, respectively, Sales and marketing $1,984 thousand and $1,936 thousand for the three months ended March 31, 2018 and 2017, respectively, General and administrative $2,058 thousand and $2,552 thousand for the three months ended March 31, 2018 and 2017, respectively and Product development $1,760 thousand and $2,770 thousand for the three months ended March 31, 2018 and 2017, respectively.