v2.4.0.6
Stock incentive plans (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Dec. 31, 2011
Mar. 31, 2011
Stock incentive plans            
Common stock shares reserved for issuance           5,511,288
Annual percentage increase alternative, increase in common stock reserved for issuance as a percentage of common stock outstanding     4.50%      
Annual fixed increase alternative, increase in shares of common stock reserved for issuance (in shares)     3,000,000      
Weighted average assumptions used for newly issued stock option grants            
Expected term     6 years 1 month 6 days      
Expected volatility (as a percent)     49.90%      
Risk free rate of return (as a percent)     1.10%      
Recognized stock-based compensation expense            
Total stock-based compensation $ 952 $ 695 $ 1,945 $ 901    
Number of Options            
Outstanding at the beginning of the period (in shares)     6,601      
Granted (in shares)     379      
Exercised (in shares)     (1,407,000)      
Cancelled/forfeited (in shares)     (192)      
Outstanding at the end of the period (in shares) 5,381   5,381   6,601  
Vested and expected to vest at the end of the period (in shares) 5,219   5,219      
Exercisable at the end of the period (in shares) 2,831   2,831      
Weighted Average Exercise Price            
Outstanding at the beginning of the period (in dollars per share)     $ 5.50      
Granted (in dollars per share)     $ 9.60      
Exercised (in dollars per share)     $ 1.34      
Cancelled/forfeited (in dollars per share)     $ 10.89      
Outstanding at the end of the period (in dollars per share) $ 6.68   $ 6.68   $ 5.50  
Vested and expected to vest at the end of the period (in dollars per share) $ 6.49   $ 6.49      
Exercisable at the end of the period (in dollars per share) $ 2.08   $ 2.08      
Weighted-Average Remaining Contract Life            
Outstanding at the beginning of the period     6 years 11 months 16 days   7 years  
Outstanding at the end of the period     6 years 11 months 16 days   7 years  
Vested and expected to vest at the end of the period     6 years 10 months 28 days      
Exercisable at the end of the period     5 years 3 months 4 days      
Aggregate Intrinsic Value            
Outstanding at the beginning of the period     30,996      
Outstanding at the end of the period 30,344   30,344   30,996  
Vested and expected to vest at the end of the period 30,268   30,268      
Exercisable at the end of the period 27,322   27,322      
Network operations
            
Recognized stock-based compensation expense            
Total stock-based compensation 105 92 111 110    
Development and technology
            
Recognized stock-based compensation expense            
Total stock-based compensation 222 125 421 161    
Selling and marketing
            
Recognized stock-based compensation expense            
Total stock-based compensation 191 134 401 174    
General and administrative
            
Recognized stock-based compensation expense            
Total stock-based compensation $ 434 $ 344 $ 1,012 $ 456