Stock incentive plans (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Recognized stock-based compensation expense
Total stock-based compensation	$ 9,398	$ 7,164	$ 4,506
Stock-based compensation expense capitalized	778	398
Network operations
Recognized stock-based compensation expense
Total stock-based compensation	1,504	1,356	888
Development and Technology
Recognized stock-based compensation expense
Total stock-based compensation	731	600	380
Selling and marketing
Recognized stock-based compensation expense
Total stock-based compensation	3,411	2,017	1,045
General and administrative
Recognized stock-based compensation expense
Total stock-based compensation	$ 3,752	$ 3,191	$ 2,193