Summary of significant accounting policies- Revenue by segment (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)
Primary revenue source
Number of reportable segments | segment			1
Revenue	$ 49,033	$ 39,075	$ 93,366	$ 73,574
DAS
Primary revenue source
Revenue	18,552	13,892	34,808	24,998
Military
Primary revenue source
Revenue	13,542	9,734	26,083	18,832
Wholesale-Wi-Fi
Primary revenue source
Revenue	7,300	5,206	14,131	10,143
Retail
Primary revenue source
Revenue	6,358	6,567	12,773	13,481
Advertising and other
Primary revenue source
Revenue	$ 3,281	$ 3,676	$ 5,571	$ 6,120