v2.4.0.6
Employee Stock and Benefit Plans Stock Option Activity (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 9 Months Ended 12 Months Ended
Sep. 30, 2012
Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]    
Balance as of December 31, 2011 (in shares) 6,312,041  
Granted (in shares) 1,322,906  
Exercised (in shares) (703,459)  
Canceled (in shares) (392,389)  
Balance as of September 30, 2012 (in shares) 6,539,099 6,312,041
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]    
Weighted average exercise price, balance as of December 31, 2011 (in dollars per share) $ 3.36  
Weighted average exercise price, granted (in dollars per share) $ 8.39  
Weighted average exercise price, exercised (in dollars per share) $ 2.84  
Weighted average exercise price, canceled (in dollars per share) $ 6.85  
Weighted average exercise price, balance as of September 30, 2012 (in dollars per share) $ 4.23 $ 3.36
Weighted average remaining contractual life 7 years 0 months 11 days 6 years 10 months 24 days
Aggregate intrinsic value $ 64,953 $ 16,012
Vested and Expected to vest - September 30, 2012 (in shares) 6,100,152  
Exercisable - September 30, 2012 (in shares) 6,537,727  
Vested and Expected to vest - September 30, 2012, weighted average exercise price (in dollars per share) $ 4.00  
Exercisable - September 30, 2012, Weighted average exercise price (in dollars per share) $ 4.23  
Vested and Expected to vest - September 30, 2012, weighted average remaining contractual life 6 years 10 months 13 days  
Exercisable - September 30, 2012, weighted average remaining contractual life 7 years