Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation Expense Included in Condensed Consolidated Statements of Income

	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

Weighted Average Assumptions for Options Granted

	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

		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

Summary of RSU Activity

	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