Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2024	Sep. 30, 2023
Credit Terms for Trade Receivables (Day)	30 days
Extended Credit Terms for Trade Receivables (Day)	60 days
Revenues	$ 135,598	$ 124,509
Impairment of Intangible Assets, Finite-Lived	2,761	0
Emerging Markets [Member]
Impairment of Intangible Assets, Finite-Lived	2,800
Customer One [Member]
Accounts and Financing Receivable, after Allowance for Credit Loss	4,100	3,500
Customer Two [Member]
Accounts and Financing Receivable, after Allowance for Credit Loss	$ 9,500	$ 4,800
Revenue Benchmark [Member] \| Customer Concentration Risk [Member] \| Customer One [Member]
Concentration Risk, Percentage	27.40%	26.70%
Revenue Benchmark [Member] \| Customer Concentration Risk [Member] \| Customer Two [Member]
Concentration Risk, Percentage	16.00%	11.70%
Revenue Benchmark [Member] \| Product Concentration Risk [Member] \| Certain Models of Oil and Gas Marine Wireless Products [Member]
Concentration Risk, Percentage	4.00%
Revenues	$ 0
Revenue Benchmark [Member] \| Product Concentration Risk [Member] \| Thermal Film [Member]
Concentration Risk, Percentage	5.00%	5.00%
Subsidiaries [Member] \| Non-US [Member]
Cash Equivalents, at Carrying Value	$ 1,100

Credit terms for trade receivables.

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Amount, after allowance for credit loss, of accounts and financing receivable. Includes, but is not limited to, notes and loan receivable.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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