Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 72,029	$ 45,793
Less accumulated depreciation	(36,779)	(26,431)
Property and equipment, net excluding construction in process	35,250	19,362
Construction in process	2,086	4,316
Property and equipment-net	37,336	23,678	$ 25,815
Network equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	59,439	37,207
Computer software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,617	3,546
Computer equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,999	2,699
Tools and test equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	488	450
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	644	352
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,842	1,533
Wireless
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 6