Stock-based Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation Expense Included in Operating Expense

Stock-based compensation expense was included in the following operating expense categories as follows (in thousands):

	Three months ended March 31,
	2016		2017
Service costs	$	198	$	125
Sales and marketing		439		406
Product development		532		91
General and administrative		797		735
Total stock-based compensation	$	1,966	$	1,357

Assumptions to Estimate Fair Value for Stock Options at Grant Date

The following weighted average assumptions were used in determining the fair value of time-vested stock option grants for the periods presented:

	Three months ended March 31,
	2016			2017
Expected life (in years)	4			4
Risk-free interest rate		1.04	%		1.72	%
Expected volatility		58	%		57	%

Summary of Stock Option Activity

Stock option activity during the three months ended March 31, 2017 is summarized as follows:

	Shares (in thousands)			Weighted average exercise price		Weighted average remaining contractual term (in years)
Balance at December 31, 2016		7,678		$	5.97		5.07
Options granted		5			2.84
Options forfeited		(326	)		4.42
Options expired		(1,367	)		6.06
Options exercised		—			—
Balance at March 31, 2017		5,990		$	6.03		5.26

Summary of Restricted Stock Awards and Restricted Stock Units

Restricted stock awards and restricted stock unit activity during the three months ended March 31, 2017 is summarized as follows:

	Shares/ Units (in thousands)			Weightedaverage grant date fair value
Unvested balance at December 31, 2016		2,757		$	3.90
Granted		—			—
Vested		(68	)		3.90
Forfeited		(204	)		4.35
Unvested balance at March 31, 2017		2,485		$	3.82