Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v2.4.0.6
Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Customer
Entity
Dec. 31, 2011
Customer
Dec. 31, 2010
Customer
Schedule Of Significant Accounting Policies [Line Items]      
Net long-lived assets, North America $ 29.9 $ 26.4  
Net long-lived assets, International subsidiaries 2.6 1.6  
Customers contribution to revenue 3.00% 3.00% 3.00%
Number of customer accounted for 3% or more of revenue 0 0 0
Primary sources of revenue 3    
Revenue recognition access period 4 years    
Renewal of additional term license 1 year    
Capitalized product development costs 3.4 2.3  
Amortization expense of development costs 1.2 1.8 1.3
Advertising costs 10.2 8.6 7.7
Software and Software Development Costs
     
Schedule Of Significant Accounting Policies [Line Items]      
Property plant and equipment, useful life 3 years    
Unamortized Software Development Costs
     
Schedule Of Significant Accounting Policies [Line Items]      
Unamortized software development costs $ 5.9 $ 3.7  
Minimum
     
Schedule Of Significant Accounting Policies [Line Items]      
Likelihood of tax benefits being realized 50.00%