Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2013

Amounts Recorded as Expense in Consolidated Statements of Income

Amounts recorded as expense in the consolidated statements of income are as follows (in thousands):

	Three Months Ended March 31,
	2012		2013
Cost of revenue	$	47	$	112
Technology and development		58		150
Sales and marketing		87		185
General and administrative		367		626
Total	$	559	$	1,073

Summary of Weighted Average Fair Value of Stock Options Granted

The following table summarizes the weighted-average fair value of stock options granted during the three months ended March 31, 2012 and 2013:

	Three Months Ended March 31,
	2012		2013
Stock options granted (in thousands)		792		452
Weighted average fair value at date of grant	$	5.34	$	11.69

Weighted Average Assumptions Used in Black-Scholes Option Pricing Model to Value Option Grants

The weighted average assumptions used in the Black-Scholes option pricing model to value option grants during the three months ended March 31, 2012 and 2013 were as follows:

	March 31,
	2012			2013
Expected volatility		55.84	%		51.62	%
Risk-free interest rate		1.37	%		1.08	%
Expected term		6.94 years			6.06 years
Dividend yield		—	%		—	%

Summary of Restricted Stock Units

The following table summarizes information about restricted stock units issued to officers, directors, and employees under our 2010 Plan:

			Weighted Average
			Grant Date
	Shares		Fair Value
	(in thousands)
Non-vested at December 31, 2012		—	$	—
Granted		357		23.76
Vested		—		—
Forfeitures		—		—
Non-vested at March 31, 2013		357	$	23.76