v3.6.0.2
Stock incentive plans - Compensation expense (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Recognized stock-based compensation expense      
Total stock-based compensation expense $ 12,805 $ 9,398 $ 7,164
Stock-based compensation expense capitalized 727 778  
Network operations      
Recognized stock-based compensation expense      
Total stock-based compensation expense 2,144 1,504 1,356
Development and technology      
Recognized stock-based compensation expense      
Total stock-based compensation expense 1,070 731 600
Selling and marketing      
Recognized stock-based compensation expense      
Total stock-based compensation expense 1,842 3,411 2,017
General and administrative      
Recognized stock-based compensation expense      
Total stock-based compensation expense $ 7,749 $ 3,752 $ 3,191