Stock Incentive Plan (Tables)
12 Months Ended
Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Summary of Assumptions to Apply Black-Scholes Option-Pricing Model

The Company used the following assumptions to apply the Black-Scholes option-pricing model:

 

     Years Ended December 31,
     2011    2012    2013

Expected dividend yield

   0.00%    0.00%    0.00%

Risk-free interest rate

   0.91% - 2.28%    0.64% - 0.87%    0.87 - 1.36%

Expected term (in years)

   5.56 - 6.25    5.56 - 6.25    6.25

Volatility

   60%    55% - 60%    55%
Summary of Stock Option Activity

The following table summarizes stock option activity (shares and intrinsic value in thousands):

 

     Number
of Options
    Weighted
Average
Exercise
Price
     Weighted
Average
Remaining
Contractual
Term
(Years)
     Aggregate
Intrinsic
Value
 

Outstanding, January 1, 2013

     2,941      $ 25.90         7.2      
       

 

 

    

Granted

     186        22.22         

Exercised

     (374 )     10.15          $ 7,213   
          

 

 

 

Forfeited

     (364 )     33.97         
  

 

 

   

 

 

       

Outstanding, December 31, 2013

     2,389      $ 26.85         6.4       $ 22,330   
  

 

 

   

 

 

    

 

 

    

 

 

 

Exercisable at December 31, 2013

     1,451      $ 23.45         5.4       $ 17,855   
  

 

 

   

 

 

    

 

 

    

 

 

 

Vested or expected to vest at December 31, 2013

     2,331      $ 26.78         6.3       $ 21,965   
  

 

 

   

 

 

    

 

 

    

 

 

 
Summary of Assumptions Used in the Monte Carlo Simulation Model

The assumptions used in the Monte Carlo simulation model include (but are not limited to) the following:

 

     Year
Ended
December  31,
2013
 

Risk-free interest rate

     0.62

Volatility

     54
Schedule of Restricted Stock Unit Activity

The following table summarizes all restricted stock unit activity (shares in thousands):

 

     Number of shares
Underlying Restricted
Stock Units
    Weighted Average
Grant Date
Fair Value
 

Unvested as of January 1, 2013

     783      $ 31.14   

Restricted stock units granted

     837        26.93   

Restricted stock units vested

     (259     31.06   

Restricted stock units forfeited

     (169     29.26   
  

 

 

   

 

 

 

Unvested as of December 31, 2013

     1,192      $ 28.47   
  

 

 

   

 

 

 
Schedule of Stock Based Compensation Allocated to Expense

The Company recognized stock based compensation expense within the accompanying consolidated statements of income as summarized in the following table (in thousands):

 

     Years Ended December 31,  
     2011      2012      2013  

Cost of revenue

   $ 316       $ 484       $ 706   

Research and development

     1,477         2,826         3,761   

Sales and marketing

     2,700         4,962         7,242   

General and administrative

     4,432         6,520         8,005   
  

 

 

    

 

 

    

 

 

 
   $ 8,925       $ 14,792       $ 19,714