Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2012
Buildings
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	40 years
Building Improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	5 years
Building Improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	10 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Useful lives, description	Lesser of lease term or useful life
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	10 years
Test Systems Manufactured Internally
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	6 years
Machinery and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	3 years
Machinery and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	5 years
Software | Minimum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	3 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Useful lives, maximum years	5 years