Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2015

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Equity Incentive Plan Activity

Equity incentive plan activity under the 2000 Plan and the 2009 Plan for the six months ended June 30, 2015 is summarized as follows:

Equity Incentive Plan Activity	Shares Available forGrant
Balance at December 31, 2014		2,708,524
Authorized		3,141,509
Granted		(1,194,751	)
Forfeited		482,321
Expired		1,250
Balance at June 30, 2015		5,138,853

Summary of Stock Option Activity under the Company's Equity-Based Plans

The following table summarizes stock option activity under the Company’s equity-based plans for the six months ended June 30, 2015:

Stock Options Activity	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value (inthousands)
Balance at December 31, 2014		6,892,810		$	6.13		8.22	$	173,338
Granted		277,200			33.42
Exercised		(1,442,538	)		3.28
Forfeited		(467,002	)		8.17
Expired		(1,250	)		10.98
Balance at June 30, 2015		5,259,220		$	8.17		7.95	$	90,346
Exercisable at June 30, 2015		1,830,015		$	4.74		7.39	$	37,723
Vested and expected to vest at June 30, 2015		5,031,744		$	7.96		7.92	$	87,501

Summary of Restricted Stock Unit Activity under the Company's Equity-Based Plans

The following table summarizes RSU activity under the Company’s equity-based plans for the six months ended June 30, 2015:

Restricted Stock Unit Activity	Number of Units			Weighted-Average Grant Date Fair Value
Nonvested at December 31, 2014		7,750		$	13.21
Granted		744,265		$	33.42
Vested		(35,639	)	$	32.66
Forfeited		(15,319	)	$	33.51
Nonvested at June 30, 2015		701,057		$	33.24

Summary of Performance Based Restricted Stock Unit Activity

The following table summarizes PSU activity under the Company’s equity-based plans for the six months ended June 30, 2015:

Performance Based Restricted Stock Unit Activity			Weighted-Average
			Grant Date
	Number of Units		Fair Value
Outstanding units at December 31, 2014		-	$	-
Granted		173,286	$	33.51
Units converted		-	$	-
Forfeited		-	$	-
Outstanding units at June 30, 2015		173,286	$	33.51

Summary of Significant Assumptions Used to Estimate Fair Value of Stock Options under Black-Scholes Model

The fair value of stock-based awards is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions:

Stock Option Assumptions	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
Expected term (in years)	6.11			5.85			6.08-6.11			6.04
Expected volatility		39	%		58	%		39	%		58	%
Risk-free interest rate		1.96	%		1.81	%	1.74-1.96%				1.80	%
Expected dividend yield		0	%		0	%		0	%		0	%

Summary of Significant Assumptions Used to Estimate Fair Value of Employee Stock Purchase Plans under Black-Scholes Model

The fair value of stock-based awards is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions:

ESPP Assumptions	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
Expected term (in years)	0.5			0.64			0.5			0.64
Expected volatility	33-43%				58	%	33-43%				58	%
Risk-free interest rate	0.07-0.08%				0.06	%	0.07-0.08%				0.06	%
Expected dividend yield		0	%		0	%		0	%		0	%

Summary of Stock-based Compensation Expense

Stock-based compensation expense for stock-based payment awards made to the Company’s employees pursuant to the equity plans was as follows (in thousands): 

	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Cost of providing services	$	1,214	$	801	$	1,972	$	1,255
Sales and marketing		1,309		774		2,226		1,291
General and administrative		1,842		1,045		3,863		2,053
Systems development and programming costs		518		303		742		471
	$	4,883	$	2,923	$	8,803	$	5,070