Note 7 - Concentrations (Details Textual)	12 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020
Property, Plant and Equipment, Net, Total	$ 18,229,000	$ 4,998,000
MEXICO
Property, Plant and Equipment, Net, Total	4,213,000	$ 1,769,000
Oulu, Finland [Member] | Nestor Cables [Member]
Property, Plant and Equipment, Net, Total	6,916,000
Keila, Estonia [Member] | Nestor Cables [Member]
Property, Plant and Equipment, Net, Total	$ 280,000
Revenue Benchmark [Member] | Customer Concentration Risk [Member]
Number of Major Customers	1	2	2
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | One Customer [Member]
Concentration Risk, Percentage	14.00%
Revenue Benchmark [Member] | Customer Concentration Risk [Member] | Two Customers [Member]
Concentration Risk, Percentage		28.00%	30.00%
Accounts Receivable [Member] | Customer Concentration Risk [Member]
Number of Major Customers	1	1
Accounts Receivable [Member] | Customer Concentration Risk [Member] | One Customer [Member]
Concentration Risk, Percentage	20.00%	17.00%