Stock incentive plans (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Recognized stock-based compensation expense
Total stock-based compensation	$ 2,256	$ 1,842	$ 6,190	$ 5,210
Stock-based compensation expense capitalized	177	130	602	291
Network operations
Recognized stock-based compensation expense
Total stock-based compensation	336	344	1,095	983
Development and Technology
Recognized stock-based compensation expense
Total stock-based compensation	319	118	546	378
Selling and marketing
Recognized stock-based compensation expense
Total stock-based compensation	600	396	1,769	1,132
General and administrative
Recognized stock-based compensation expense
Total stock-based compensation	$ 1,001	$ 984	$ 2,780	$ 2,717