Summary of significant accounting policies- Revenue by segment (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)
Primary revenue source
Number of reportable segments | segment	1
Revenue	$ 44,333	$ 34,499
DAS
Primary revenue source
Revenue	16,256	11,106
Military
Primary revenue source
Revenue	12,541	9,098
Wholesale-Wi-Fi
Primary revenue source
Revenue	6,831	4,937
Retail
Primary revenue source
Revenue	6,415	6,914
Advertising and other
Primary revenue source
Revenue	$ 2,290	$ 2,444