Note 5 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Effective Income Tax Rate Reconciliation, GILTI, Amount	$ 0	$ 323,000
Effective Income Tax Rate Reconciliation, Percent	33.00%	56.60%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Deferred Tax Assets, Net	$ 4,687,000	$ 3,766,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	50,000.00
Unrecognized Tax Benefits, Income Tax Penalties Expense	1,000	800,000
Unrecognized Tax Benefits, Interest on Income Taxes Expense	4,000	300,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued	15,000	$ 14,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	17,000		$ 16,000
Domestic Tax Authority [Member]
Deferred Tax Assets, Net	2,300,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued	0
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 0
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Operating Loss Carryforwards	$ 5,000,000
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	1,100,000
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	600,000
Capital Loss Carryforward	300,000
Capital Loss Carryforward, Tax Effect	100,000
State and Local Jurisdiction [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	100,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued	15,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	17,000
Foreign Tax Authority [Member]
Unrecognized Tax Benefits, Income Tax Penalties Accrued	0
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	0
Foreign Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	200,000
Foreign Tax Authority [Member] | Brazilian Federal Revenue Office [Member]
Operating Loss Carryforwards, Not Subject to Expiration	1,700,000
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	600,000
Foreign Tax Authority [Member] | State Administration of Taxation, China [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	200,000
Operating Loss Carryforwards, Subject to Expiration	1,000,000
Foreign Tax Authority [Member] | Mexican Tax Authority [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	300,000
Operating Loss Carryforwards, Subject to Expiration	$ 1,100,000