v3.4.0.3
Summary of significant accounting policies (Details 3) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2016
Dec. 31, 2015
Foreign Currency Translation    
Cumulative foreign currency translation adjustments, net of tax in accumulated other comprehensive income $ (1,032) $ (1,160)
Income tax expense related to foreign currency translation adjustments $ 0 $ 0
DAS license agreements | Minimum    
Revenue recognition    
Term of the arrangement used to determine revenue recognition 5 years  
DAS license agreements | Maximum    
Revenue recognition    
Term of the arrangement used to determine revenue recognition 20 years  
Wholesale - Wi-Fi | Minimum    
Revenue recognition    
Term of the arrangement used to determine revenue recognition 1 year  
Wholesale - Wi-Fi | Maximum    
Revenue recognition    
Term of the arrangement used to determine revenue recognition 5 years