Stock-Based Compensation (Tables)
 3 Months Ended
Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions
The fair value of the Company’s stock-based awards was estimated based on the following assumptions:
 
Three Months Ended
March 31,
 
2015
 
2014
Option grants:
 
 
 
Expected volatility
31
%
 
37 - 40%

Expected dividends
—

 
—

Expected term of options (in years)
3.5

 
3.5

Risk-free interest rate
1.1
%
 
1.0
%
ESPP: (i)
 
 
 
Expected volatility
29
%
 
36
%
Expected dividends
—

 
—

Expected term of ESPP (in years)
0.5

 
0.5

Risk-free interest rate
0.1
%
 
0.1
%
PRSUs with market conditions:
 
 
 
Expected volatility
30% - 39%

 
—

Expected dividends
—

 
—

Risk-free interest rate
1.0
%
 
—

____________________
(i)
ESPP purchases are scheduled for the last day of January and July of each year.
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs
The allocations of the stock-based compensation, net of estimated income tax benefit, for the three months ended March 31, 2015 and 2014 are as follows (in thousands):
 
Three Months Ended
March 31,
 
2015
 
2014
Cost of service revenues
$
1,539

 
$
1,464

Research and development
5,060

 
4,662

Sales and marketing
4,769

 
4,706

General and administrative
3,722

 
3,414

Total stock-based compensation
15,090

 
14,246

Estimated tax benefit of stock-based compensation
(4,040
)
 
(3,862
)
Total stock-based compensation, net of estimated tax benefit
$
11,050

 
$
10,384
Schedule of Share-based Compensation, Stock Options, Activity
A summary of stock option activity through March 31, 2015 is presented below (in thousands, except per share amounts):
 
 
 
 
 
 
 
Number of
Shares
 
Weighted-
Average
Exercise Price
Per Share
 
Weighted
Average
Remaining
Contractual
Term (Years)
 
Aggregate
Intrinsic
Value
Outstanding at December 31, 2014
7,186

 
$
35.82

 
4.25
 
$
31,514

Granted
464

 
$
42.50

 
 
 
 
Exercised
(601
)
 
$
22.96

 
 
 
 
Forfeited or expired
(208
)
 
$
36.17

 
 
 
 
Outstanding at March 31, 2015
6,841

 
$
37.40

 
4.24
 
$
48,057

Exercisable at March 31, 2015
3,950

 
$
36.99

 
3.41
 
$
30,817
Schedule of Share-based Compensation, Restricted Stock Units Award Activity
A summary of RSU activity, excluding PRSUs, through March 31, 2015 is presented below (in thousands, except per share amounts):
 
 
 
Number of
Shares
 
Weighted-
Average
Grant Date
Fair Value
Outstanding at December 31, 2014
2,513

 
—

Awarded
835

 
$
42.50

Released
(167
)
 
$
40.30

Forfeited
(129
)
 
$
37.60

Outstanding at March 31, 2015
3,052

 
—
Schedule of Nonvested Performance-based Units Activity
A summary of PRSU activity based upon PRSUs granted in 2013 and 2014, certified and actually achieved through the three months ended March 31, 2015 is presented below (in thousands):
 
 Number of
Shares
Outstanding at December 31, 2014
306

Achieved
138

Released
(136
)
Forfeited
(20
)
Outstanding at March 31, 2015
288

The fair value of PRSUs released during the three months ended March 31, 2015 was approximately $5.1 million.
A summary of PRSU activity through the three months ended March 31, 2015 for awards that have not been certified by the Compensation Committee of the Board of Directors as achieved is presented below (in thousands):
 
 Number of
Shares
Outstanding at December 31, 2014
—

Granted
237

Forfeited
(2
)
Outstanding at March 31, 2015
235