v3.19.1
Stock incentive plans - Compensation expense (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Recognized stock-based compensation expense    
Total stock-based compensation expense $ 2,344 $ 3,126
Stock-based compensation expense capitalized 230 186
Network operations    
Recognized stock-based compensation expense    
Total stock-based compensation expense 506 537
Development and technology    
Recognized stock-based compensation expense    
Total stock-based compensation expense 303 278
Selling and marketing    
Recognized stock-based compensation expense    
Total stock-based compensation expense 529 473
General and administrative    
Recognized stock-based compensation expense    
Total stock-based compensation expense $ 1,006 $ 1,838