Annual report pursuant to Section 13 and 15(d)

Note 6 - Income Taxes (Details Textual)

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Note 6 - Income Taxes (Details Textual) - USD ($)
12 Months Ended 24 Months Ended
Sep. 30, 2023
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2021
Accrued Income Taxes, Current $ 84,000 $ 84,000 $ 1,791,000  
Domestic Tax Authority [Member]        
Operating Loss Carryforwards 0 $ 0 0  
Open Tax Year   2017 2018 2019 2020 2021 2022 2023    
Foreign Tax Authority [Member] | Finnish Tax Administration [Member]        
Operating Loss Carryforwards $ 1,000 $ 1,000 4,000  
Foreign Tax Authority [Member] | Finnish Tax Administration [Member] | Nestor Cables [Member]        
Open Tax Year 2018 2019 2020 2021 2022 2023      
State and Local Jurisdiction [Member]        
Open Tax Year   2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023    
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]        
Tax Credit Carryforward, Amount $ 255,000 $ 255,000 $ 292,000  
State and Local Jurisdiction [Member] | Research and Development and Alternative Minimum Tax Credit Carryforwards [Member]        
Deferred Tax Assets, Valuation Allowance       $ 0