Note 11 - Income Taxes - Income Tax Reconciliation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income taxes based on U.S. statutory rate of 21% and 34%, respectively	$ 928,000	$ 1,247,000
Non-deductible meals and entertainment	5,000	6,000
Deemed foreign repatriation		468,000
Domestic manufacturer's deduction		(97,000)
FDII deduction	(56,000)
Foreign taxes	(123,000)	(500,000)
State taxes	89,000	82,000
Effect of Federal tax rate reduction from 34% to 21%		(53,000)
Other	(54,000)	(116,000)
	$ 789,000	$ 1,037,000