Summary of significant accounting policies- Revenue by segment (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)
Primary revenue source
Number of reportable segments | segment			1
Revenue	$ 40,796	$ 37,186	$ 114,370	$ 100,855
DAS
Primary revenue source
Revenue	15,959	13,142	40,957	34,863
Military
Primary revenue source
Revenue	10,137	5,257	28,969	13,003
Retail
Primary revenue source
Revenue	6,619	7,754	20,100	24,608
Wholesale - Wi-Fi
Primary revenue source
Revenue	5,888	5,454	16,031	15,096
Advertising and other
Primary revenue source
Revenue	$ 2,193	$ 5,579	$ 8,313	$ 13,285