Balance Sheet Information - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Allowance for doubtful accounts	$ 0.1		$ 0.1
Consigned inventory with customers	1.0		1.1
Allowance for inventory losses	2.0		1.9
Depreciation and amortization expense	$ 0.7	$ 0.7
Building [Member]
Property, Plant and Equipment [Line Items]
Useful lives of the assets	30 years
Office equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Manufacturing and test equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Motor vehicles [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	7 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Standard term of accounts receivable	30 days
Minimum [Member] | Computer equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Standard term of accounts receivable	60 days
Useful lives of the assets	1 year
Maximum [Member] | Computer equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years