Note 13 - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Inventory obsolescence reserve	$ 41,000	$ 53,000
Deferred revenue	54,000	91,000
Organization costs	117,000	117,000
Deferred compensation		97,000
Depreciation and amortization, deferred tax assets	33,000	2,000
Operating lease liabilities	76,000
Miscellaneous accrued expenses	20,000	23,000
Domestic net operating loss carryforwards	649,000	451,000
Foreign net operating loss carryforwards	3,311,000	3,118,000
Valuation allowance	(4,117,000)	(3,845,000)
	184,000	107,000
Deferred tax liabilities:
Operating lease right-to-use assets	77,000
Foreign currency exchange	107,000	107,000
	184,000	107,000
Net deferred tax assets (liabilities)