Note 5 - Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Property, plant and equipment, gross	$ 72,465,000	$ 64,877,000
Accumulated depreciation and amortization	(44,932,000)	(42,353,000)
	27,533,000	22,524,000
Land [Member]
Property, plant and equipment, gross	4,485,000	4,485,000
Buildings Improvements and Leaseholds [Member]
Property, plant and equipment, gross	19,140,000	16,601,000
Machinery, Equipment and Fixtures [Member]
Property, plant and equipment, gross	$ 48,840,000	$ 43,791,000