Stock-based Compensation

6 Months Ended

Jun. 30, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

(10)  Stock-based Compensation

Stock‑based compensation expense included in the Company’s condensed consolidated statements of income during the periods presented is as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
	(unaudited)
Stock-based compensation expense:
Marketing	$	266	$	106	$	499	$	198
Technology and development		787		296		1,406		522
Customer service and operations		209		107		402		184
General and administrative		1,071		450		1,950		833
Total stock-based compensation	$	2,333	$	959	$	4,257	$	1,737

(a)  Stock Options

The fair value of options granted was estimated at the date of the grant using a Black-Scholes option-pricing model. The weighted-average grant date fair value of options granted was $7.99 and $8.98 for the three months ended June 30, 2014 and 2013, respectively, and $11.71 and $8.98 for the six months ended June 30, 2014 and 2013, respectively. The following table presents the weighted-average assumptions for options granted during the periods presented:

	Three Months Ended June 30,		Six Months Ended June 30,
	2014	2013	2014	2013
	(unaudited)
Expected term (in years)	5.6	6.2	6.2	6.2
Risk-free interest rate	1.67%	1.02%	2.03%	1.02%
Dividend yield	None	None	None	None
Volatility rate	36%	44%	43%	44%

Stock option activity and related information during the period indicated was as follows (unaudited):

		Weighted-			Exercisable
		Average			Weighted-
	Options	Exercise		Options	Average
	Outstanding	Price		Exercisable	Exercise Price
Outstanding as of December 31, 2013	6,045,912	$	7.72	3,195,701	$	3.64
Granted	1,277,572		26.20
Exercised	(517,146)		3.43
Forfeited and cancelled	(64,620)		19.07
Outstanding as of June 30, 2014	6,741,718	$	11.44	3,433,826	$	5.50

As of June 30, 2014, there were 6,671,244options that had vested or are expected to vest with a weighted-average exercise price of $11.36 and a weighted-average remaining contractual life of 6.9 years. As of December 31, 2013, there were 5,988,706 options that had vested and were expected to vest with a weighted-average exercise price of $7.67 and a weighted-average remaining contractual life of 6.6 years.

The aggregate intrinsic value of options outstanding was $101.8 million and the aggregate intrinsic value of options exercisable was $71.6 million as of June 30, 2014.

The total intrinsic value of options exercised was approximately $3.6 million and $807,000 for the three months ended June 30, 2014 and 2013, respectively, and $11.4 million and $4.0 million for the six months ended June 30, 2014 and 2013, respectively.

As of June 30, 2014, there was $23.4 million of total unrecognized compensation expense related to option grants, which is expected to be recognized over a weighted-average period of 2.6years.

(b)  Restricted Stock Units

The Company began granting RSUs to its employees in January 2014. The fair value of the RSUs is determined using the fair value of the Company’s common stock on the date of grant. These RSUs typically vest and become exercisable annually over four years. Stock-based compensation expense is amortized on a straight-line basis over the requisite service period.

The following table shows a summary of RSU activity for the six months ended June 30, 2014 (unaudited):

	Outstanding RSUs
		Weighted-
		Average
		Grant Date
	Shares	FairValue
Unvested as of January 1, 2014	—	$	—
Granted	258,895		19.41
Vested	—		—
Forfeited and cancelled	(16,250)		24.54
Unvested as of June 30, 2014	242,645	$	19.07

As of June 30, 2014, there was $4.0 million of total unrecognized compensation expense related to RSUs, which is expected to be recognized over a weighted-average period of 2.5years.