Financial Statement Details - Summary of Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 73,728	$ 72,235
Less—accumulated depreciation and amortization	(68,449)	(62,334)
Property and equipment, Net	5,279	9,901
Test equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	53,019	52,108
Computer equipment and purchased software
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	11,247	10,814
Product tooling
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	3,535	3,204
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	1,824	2,015
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 4,103	$ 4,094