Property, Plant and Equipment (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Property, plant and equipment
Property, plant and equipment, gross	$ 22,536,000		$ 22,536,000		$ 21,482,000
Less accumulated depreciation	(13,471,000)		(13,471,000)		(12,851,000)
Property, plant and equipment, net	9,065,000		9,065,000		8,631,000
Depreciation expense	348,000	325,000	661,000	640,000
Land
Property, plant and equipment
Property, plant and equipment, gross	290,000		290,000		290,000
Building and improvements
Property, plant and equipment
Property, plant and equipment, gross	3,881,000		3,881,000		3,713,000
Machinery, equipment, tools and dies
Property, plant and equipment
Property, plant and equipment, gross	14,295,000		14,295,000		13,483,000
Furniture, fixtures and other
Property, plant and equipment
Property, plant and equipment, gross	$ 4,070,000		$ 4,070,000		$ 3,996,000