Share-based Compensation Plans and Awards - Stock-based Compensation Expense (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended 9 Months Ended
Sep. 30, 2012
Jun. 30, 2011
Jun. 30, 2011
Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation included in net loss $ 8,046 $ 7,755 $ 22,102 $ 23,986
Restricted stock units (RSUs) [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Restricted stock awards vested (in shares)       1,257
Executive officers [Member] | Performance and Market-based Stock Option and Restricted Stock Awards [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation included in net loss     5,051  
Executive officers [Member] | Performance and market-based stock option [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Performance and market-based stock options vested     1,625  
Executive officers [Member] | Restricted stock units (RSUs) [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Restricted stock awards vested (in shares)     1,000  
Service costs [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation included in net loss 672 757 1,341 2,141
Sales and marketing [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation included in net loss 1,400 1,405 3,441 4,521
Product development [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation included in net loss 1,396 1,403 3,649 5,169
General and administrative [Member]
       
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Total stock-based compensation included in net loss $ 4,578 $ 4,190 $ 13,671 $ 12,155