5. Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Expected Life	3 to 39 years
Property, plant and equipment, gross	$ 46,002	$ 41,504
Less accumulated depreciation	(29,503)	(25,968)
Property, plant and equipment, net	16,499	15,536
Construction in progress	1,890	371
Property, plant and equipment, net plus construction in progress	18,389	15,907
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 324	292
Office buildings [Member]
Property, Plant and Equipment [Line Items]
Expected Life	39 years
Property, plant and equipment, gross	$ 4,785	4,280
Production facilities [Member]
Property, Plant and Equipment [Line Items]
Expected Life	10-20 years
Property, plant and equipment, gross	$ 11,509	10,734
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Expected Life	3-15 years
Property, plant and equipment, gross	$ 27,493	24,492
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Expected Life	3-20 years
Property, plant and equipment, gross	$ 1,892	$ 1,706