Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Intangible assets, gross	$ 19,944	$ 19,233
Less accumulated amortization	(10,216)	(9,410)
Intangible assets, net	9,728	9,823
Horizon Software [Member]
Intangible assets, gross	18,589	17,879
ZTEsoft Telecom Software [Member]
Intangible assets, gross	470	469
Contractual Relationships [Member]
Intangible assets, gross	$ 885	$ 885