Basis of Presentation - Prior Period Reclassifications (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Basis Of Presentation And Significant Accounting Policies [Line Items]          
General and administrative expense $ 7,498 $ 9,258 $ 23,450 $ 27,841  
Product development expense 4,652 6,936 15,614 20,543  
Sales and marketing expense 6,031 5,602 19,610 15,343  
Cost of services 5,370 9,597 19,887 29,296  
Other income, net (31) 178 39,131 3,024  
Property and equipment, net $ 11,929   $ 11,929   $ 14,568
Reclassification          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
General and administrative expense   (600)   (2,400)  
Product development expense   400   1,600  
Sales and marketing expense   200   500  
Cost of services   100   200  
Depreciation   600      
Other income, net   (500)      
Property and equipment, net   $ (1,100)   $ (1,100)