Related Party Transactions (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jul. 01, 2016
Jun. 30, 2018
Jun. 30, 2018
Jun. 30, 2017
Related Party Transaction [Line Items]        
Revenues   $ 8,595 $ 16,079 $ 18,056
Content And Marketing Services | Company Owned by Employee        
Related Party Transaction [Line Items]        
Monthly revenue received per agreement $ 5      
Revenues     0 $ 5
Products        
Related Party Transaction [Line Items]        
Revenues   3,699 6,694  
Maintenance And Content Services        
Related Party Transaction [Line Items]        
Revenues   3,491 6,631  
Professional Services        
Related Party Transaction [Line Items]        
Revenues   $ 1,405 $ 2,754