Revenue (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Jan. 01, 2016
Disaggregation of Revenue [Line Items]
Total net revenue	$ 38,307	$ 37,641
Accounts receivable, net	14,948		$ 17,375
Prepaid expenses and other current assets	5,624		5,327
Total current assets	129,979		128,794
Other assets	507		223
Total assets	207,246		205,050
Accrued compensation and employee benefits	3,479		6,611
Accounts payable and accrued expenses	5,484		5,273
Deferred revenue	14,992		13,891
Total current liabilities	23,955		25,775
Other liabilities	1,406		1,776
Total liabilities	28,528		30,916
Accumulated deficit	(3,206)		(6,819)
Total stockholders’ equity	178,718		174,134
Total liabilities and stockholders’ equity	207,246		205,050
Net revenue	38,307	37,641
Cost of revenue	1,643	2,037
Sales and marketing	12,682	13,623
Total costs and expenses	33,822	36,370
Income from operations	4,485	1,271
Income before income taxes	4,665	1,247
Income tax expense/(benefit)	1,053	(38)
Net income	$ 3,612	$ 1,285
Basic earnings per share (in dollars per share)	$ 0.14	$ 0.05
Diluted earnings per share (in dollars per share)	$ 0.14	$ 0.05
Deferred income taxes	$ 329	$ 977
Decrease in accounts receivable	2,353	1,070
Increase in prepaid expenses and other assets, net	(897)	(1,368)
Decrease in accrued compensation and employee benefits	(3,132)	(2,553)
(Decrease) / increase in accounts payable and accrued expenses	280	808
Increase in deferred revenue	1,101	1,161
Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		37,641
Accounts receivable, net			17,375
Prepaid expenses and other current assets			5,327
Total current assets			128,794
Deferred tax assets, net			6,124
Other assets			223
Total assets			205,050
Accrued compensation and employee benefits			6,611
Accounts payable and accrued expenses			5,273
Deferred revenue			13,891
Total current liabilities			25,775
Other liabilities			1,776
Total liabilities			30,916
Accumulated deficit			(6,819)
Total stockholders’ equity			174,134
Total liabilities and stockholders’ equity			205,050
Net revenue		37,641
Cost of revenue		2,037
Sales and marketing		13,623
Total costs and expenses		36,370
Income from operations		1,271
Income before income taxes		1,247
Income tax expense/(benefit)		(38)
Net income		$ 1,285
Basic earnings per share (in dollars per share)		$ 0.05
Diluted earnings per share (in dollars per share)		$ 0.05
Deferred income taxes		$ 977
Decrease in accounts receivable		1,070
Increase in prepaid expenses and other assets, net		(1,368)
Decrease in accrued compensation and employee benefits		(2,553)
(Decrease) / increase in accounts payable and accrued expenses		808
Increase in deferred revenue		1,161
Accounting Standards Update 2014-09 | As Reported
Disaggregation of Revenue [Line Items]
Total net revenue		35,760
Accounts receivable, net			16,399
Prepaid expenses and other current assets			5,102
Total current assets			127,593
Deferred tax assets, net			6,500
Other assets			118
Total assets			204,120
Accrued compensation and employee benefits			6,490
Accounts payable and accrued expenses			5,271
Deferred revenue			14,113
Total current liabilities			25,874
Other liabilities			1,792
Total liabilities			31,031
Accumulated deficit			(7,864)
Total stockholders’ equity			173,089
Total liabilities and stockholders’ equity			204,120
Net revenue		35,760
Cost of revenue		1,909
Sales and marketing		13,491
Total costs and expenses		36,110
Income from operations		(350)
Income before income taxes		(374)
Income tax expense/(benefit)		(686)
Net income		$ 312
Basic earnings per share (in dollars per share)		$ 0.01
Diluted earnings per share (in dollars per share)		$ 0.01
Deferred income taxes		$ 329
Decrease in accounts receivable		1,777
Increase in prepaid expenses and other assets, net		(1,469)
Decrease in accrued compensation and employee benefits		(2,720)
(Decrease) / increase in accounts payable and accrued expenses		812
Increase in deferred revenue		2,339
Accounting Standards Update 2014-09 | Adoption of ASU 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		1,881
Accounts receivable, net			976
Prepaid expenses and other current assets			225
Total current assets			1,201
Deferred tax assets, net			(376)
Other assets			105
Total assets			930
Accrued compensation and employee benefits			121
Accounts payable and accrued expenses			2
Deferred revenue			(222)
Total current liabilities			(99)
Other liabilities			(16)
Total liabilities			(115)
Accumulated deficit			1,045
Total stockholders’ equity			1,045
Total liabilities and stockholders’ equity			$ 930
Net revenue		1,881
Cost of revenue		128
Sales and marketing		132
Total costs and expenses		260
Income from operations		1,621
Income before income taxes		1,621
Income tax expense/(benefit)		648
Net income		$ 973
Basic earnings per share (in dollars per share)		$ 0.04
Diluted earnings per share (in dollars per share)		$ 0.04
Deferred income taxes		$ 648
Decrease in accounts receivable		(707)
Increase in prepaid expenses and other assets, net		101
Decrease in accrued compensation and employee benefits		167
(Decrease) / increase in accounts payable and accrued expenses		(4)
Increase in deferred revenue		(1,178)
Transactions
Disaggregation of Revenue [Line Items]
Total net revenue	6,313	5,132
Transactions | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		5,132
Transactions | Accounting Standards Update 2014-09 | As Reported
Disaggregation of Revenue [Line Items]
Total net revenue		4,962
Transactions | Accounting Standards Update 2014-09 | Adoption of ASU 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		170
National online advertising
Disaggregation of Revenue [Line Items]
Total net revenue	6,767	10,001
National online advertising | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		10,001
National online advertising | Accounting Standards Update 2014-09 | As Reported
Disaggregation of Revenue [Line Items]
Total net revenue		8,928
National online advertising | Accounting Standards Update 2014-09 | Adoption of ASU 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		1,073
Local marketplace
Disaggregation of Revenue [Line Items]
Total net revenue	21,875	18,619
Local marketplace | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		18,619
Local marketplace | Accounting Standards Update 2014-09 | As Reported
Disaggregation of Revenue [Line Items]
Total net revenue		18,435
Local marketplace | Accounting Standards Update 2014-09 | Adoption of ASU 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		184
Publishing and other
Disaggregation of Revenue [Line Items]
Total net revenue	$ 3,352	3,889
Publishing and other | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		3,889
Publishing and other | Accounting Standards Update 2014-09 | As Reported
Disaggregation of Revenue [Line Items]
Total net revenue		3,435
Publishing and other | Accounting Standards Update 2014-09 | Adoption of ASU 2014-09
Disaggregation of Revenue [Line Items]
Total net revenue		$ 454
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Accumulated deficit				$ 600