Balance Sheet Information - Summary of Property and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 29,070	$ 28,598
Less: Accumulated depreciation and amortization	(15,948)	(15,397)
Land	1,770	1,770
Property and equipment, net	14,892	14,971
Building [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	6,207	6,207
Computers and office equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	9,966	9,818
Manufacturing and test equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	10,678	10,415
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	1,203	1,204
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	899	837
Motor vehicles [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 117	$ 117