v2.4.0.6
Stockholders' Equity (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Shares:    
Balance as of December 31, 2012 1,626,606  
Granted 371,750  
Exercised (23,401)  
Forfeited (39,375)  
Cancelled (24,123)  
Balance as of March 31, 2013 1,911,457 1,626,606
Exercisable as of March 31, 2013 848,436  
Options vested and expected to vest as of March 31, 2013 1,911,457  
Weighted Average Exercise Price (in dollars per share):    
Balance as of December 31, 2012 $ 14.90  
Granted $ 21.92  
Exercised $ 13.96  
Forfeited $ 19.13  
Cancelled $ 30.63  
Balance as of March 31, 2013 $ 15.99 $ 14.90
Exercisable as of March 31, 2013 $ 15.78  
Options vested and expected to vest as of March 31, 2013 $ 15.99  
Weighted Average Remaining Contractual Term in Years Beginning balance 8 years 1 month 10 days 7 years 9 months 29 days
Exercisable at March 31, 2013 Weighted Average Remaining Contractual Term in Years 6 years 11 months 16 days  
Options vested and expected to vest as of March 31, 2013, Weighted Average Remaining Contractual Term in Years 8 years 1 month 10 days  
Aggregate Intrinsic Value $ 21,635 $ 11,358
Exercisable at March 31, 2013, Aggregate Intrinsic Value 10,482  
Options vested and expected to vest as of March 31, 2013, Aggregate Intrinsic Value $ 21,635