Property, Plant and Equipment (Details) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Property, plant and equipment
Property, plant and equipment, gross	$ 21,681,000		$ 21,482,000
Less accumulated depreciation	(13,133,000)		(12,851,000)
Property, plant and equipment, net	8,548,000		8,631,000
Depreciation expense	329,000	315,000
Land
Property, plant and equipment
Property, plant and equipment, gross	290,000		290,000
Building and improvements
Property, plant and equipment
Property, plant and equipment, gross	3,726,000		3,713,000
Machinery, equipment, tools and dies
Property, plant and equipment
Property, plant and equipment, gross	13,628,000		13,483,000
Furniture, fixtures and other
Property, plant and equipment
Property, plant and equipment, gross	$ 4,037,000		$ 3,996,000

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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