v3.8.0.1
Stock incentive plans - Compensation expense (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Recognized stock-based compensation expense        
Total stock-based compensation $ 3,684 $ 3,006 $ 11,016 $ 9,690
Stock-based compensation expense capitalized 163 182 530 553
Network operations        
Recognized stock-based compensation expense        
Total stock-based compensation 552 483 1,660 1,660
Development and technology        
Recognized stock-based compensation expense        
Total stock-based compensation 275 267 825 830
Selling and marketing        
Recognized stock-based compensation expense        
Total stock-based compensation 524 424 1,589 1,431
General and administrative        
Recognized stock-based compensation expense        
Total stock-based compensation $ 2,333 $ 1,832 $ 6,942 $ 5,769