Note 11 - Income Taxes - Income Tax Reconciliation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income taxes based on U.S. statutory rate of 34%	$ 1,247,000	$ 1,419,000
Non-deductible meals and entertainment	6,000	5,000
Deemed foreign repatriation	468,000
Domestic manufacturer's deduction	(97,000)	(71,000)
Foreign taxes	(500,000)	(169,000)
State taxes	82,000	66,000
Effect of Federal tax rate reduction from 35% to 21%	(53,000)
Other	(116,000)	(243,000)
	$ 1,037,000	$ 1,007,000