Property, Plant, and Equipment - Property, Plant, and Equipment (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	$ 84,006,000	$ 79,124,000
Less: accumulated depreciation	(49,186,000)	(47,380,000)
Property, Plant and Equipment, Net, Total	34,820,000	31,744,000
Depreciated property, plant, and equipment	2,777,000	1,593,000
Buildings include rental property	5,750,000	5,750,000
Accumulated depreciation	2,332,000	2,185,000
Land [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	3,951,000	3,951,000
Building [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	18,371,000	18,371,000
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	13,186,000	11,723,000
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	4,925,000	4,327,000
Computer hardware and software [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	26,907,000	25,763,000
Manufacturing test equipment [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	12,876,000	11,522,000
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property,Plant and equipment,gross	$ 3,790,000	$ 3,467,000