Description of Business and Summary of Significant Accounting Policies and Practices (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Allowance for Doubtful Accounts and Advertiser Credit Activity

The allowance for doubtful accounts activity for the periods indicated is as follows (in thousands):

	Balance at beginning of period		Charged to costs and expenses		Write-offs, net of recoveries		Balance at end of period
December 31, 2015		583		61		160		484
December 31, 2016		484		90		75		499
December 31, 2017		499		161		34		626

Allowance for Advertiser Credits

The allowance for advertiser credits is the Company’s best estimate of the amount of expected future reductions in advertisers’ payment obligations related to delivered services. The Company determines the allowance for advertiser credits and adjustments based on analysis of historical credits.

The allowance for advertiser credits activity for the periods indicated is as follows (in thousands):

	Balance at beginning of period		Additions charged against revenue		Credits processed		Balance at end of period
December 31, 2015		1,018		263		756		525
December 31, 2016		525		1,592		1,179		938
December 31, 2017		938		65		390		613

Schedule of Concentration of Risk Based on Consolidated Revenue

The advertisers representing more than 10% of consolidated revenue are as follows (in percentages):

	Years ended December 31,
	2015			2016			2017
Advertiser A		29	%		23	%		21	%
Advertiser B		19	%		23	%		17	%

Schedule of Concentration of Risk Based on Accounts Receivable

The outstanding receivable balance for each advertiser representing more than 10% of consolidated accounts receivable is as follows (in percentages):

	At December 31,
	2016			2017
Advertiser A		11	%		17	%
Advertiser B		30	%		31	%
Advertiser C		15	%		10	%

Computation of Net Income (Loss) per Share Basic and Diluted

The following table presents the computation of basic net income (loss) per share for the periods ended (in thousands, except per share amounts):

	Twelve months ended December 31,
	2015						2016						2017
	Class A			Class B			Class A			Class B			Class A			Class B
Basic net income (loss) per share:
Numerator:
Net loss from continuing operations	$	(81	)	$	(516	)	$	(10,452	)	$	(73,614	)	$	(786	)	$	(5,301	)
Dividends applicable to participating securities		—			(37	)		—			—			—			(355	)
Net loss from continuing operations applicable    to common stockholders	$	(81	)	$	(553	)	$	(10,452	)	$	(73,614	)	$	(786	)	$	(5,656	)
Discontinued operations, net of tax		3,472			23,846			—			—			—			—
Net income (loss) applicable to common    stockholders	$	3,391		$	23,293		$	(10,452	)	$	(73,614	)	$	(786	)	$	(5,656	)
Denominator:
Weighted average number of shares    outstanding used to calculate basic net    income (loss) per share		5,233			35,935			5,190			36,550			5,056			37,657
Basic net income (loss) per share:
Net loss from continuing operations applicable    to common stockholders	$	(0.01	)	$	(0.01	)	$	(2.01	)	$	(2.01	)	$	(0.16	)	$	(0.15	)
Discontinued operations, net of tax		0.66			0.66			—			—			—			—
Basic net income (loss) per share applicable to    common stockholders	$	0.65		$	0.65		$	(2.01	)	$	(2.01	)	$	(0.16	)	$	(0.15	)

The following table presents the computation of diluted net income (loss) per share for the periods ended (in thousands, except per share amounts):

	Twelve months ended December 31,
	2015						2016						2017
	Class A			Class B			Class A			Class B			Class A			Class B
Diluted net income (loss) per share:
Numerator:
Net loss from continuing operations	$	(81	)	$	(516	)	$	(10,452	)	$	(73,614	)	$	(786	)	$	(5,301	)
Dividends applicable to participating securities		—			(37	)		—			—			—			(355	)
Reallocation of net loss for Class A shares as    a result of conversion of Class A to Class B    shares		—			(81	)		—			(10,452	)		—			(786	)
Net loss from continuing operations    applicable to common stockholders	$	(81	)	$	(634	)	$	(10,452	)	$	(84,066	)	$	(786	)	$	(6,442	)
Discontinued operations, net of tax		3,472			23,846			—			—			—			—
Reallocation of discontinued operations for    Class A shares as a result of conversion of    Class A to Class B share		—			3,472			—			—			—			—
Diluted discontinued operations, net of tax	$	3,472		$	27,318		$	—		$	—		$	—		$	—
Net income (loss) applicable to common    stockholders	$	3,391		$	26,684		$	(10,452	)	$	(84,066	)	$	(786	)	$	(6,442	)
Weighted average number of shares    outstanding used to calculate basic net    income (loss) per share		5,233			35,935			5,190			36,550			5,056			37,657
Conversion of Class A to Class B common    shares outstanding		—			5,233			—			5,190			—			5,056
Weighted average number of shares    outstanding used to calculate diluted net    income (loss) per share		5,233			41,168			5,190			41,740			5,056			42,713
Diluted net income (loss) per share:
Net loss from continuing operations applicable    to common stockholders	$	(0.01	)	$	(0.01	)	$	(2.01	)	$	(2.01	)	$	(0.16	)	$	(0.15	)
Discontinued operations, net of tax		0.66			0.66			—			—			—			—
Diluted net income (loss) per share applicable    to common stockholders	$	0.65		$	0.65		$	(2.01	)	$	(2.01	)	$	(0.16	)	$	(0.15	)