v2.4.0.8
Summary of Significant Accounting Policies (Details 4)
9 Months Ended
Sep. 30, 2014
item
Capitalized Content Development Costs  
Useful life of capitalized content development costs 5 years
Rebate Reserve  
Period of teaching in designated low-income school to get rebate 5 years
Period start with in teaching in designated low-income school to get rebate 6 years
Segment and Geographic Information  
Number of reportable segments 1
Computer hardware | Minimum
 
Property and equipment  
Useful life 3 years
Computer hardware | Maximum
 
Property and equipment  
Useful life 5 years
Furniture and office equipment | Minimum
 
Property and equipment  
Useful life 5 years
Furniture and office equipment | Maximum
 
Property and equipment  
Useful life 7 years
Leasehold improvements | Minimum
 
Property and equipment  
Useful life 4 years
Leasehold improvements | Maximum
 
Property and equipment  
Useful life 10 years
Internally-developed software
 
Property and equipment  
Useful life 3 years