Note 1 - Significant Accounting Policies (Details Textual)	3 Months Ended	9 Months Ended
Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Sep. 30, 2025 USD ($)
Cash and Cash Equivalent	$ 2,833,000		$ 2,833,000		$ 26,338,000
Restricted Cash, Current	$ 2,000,000	$ (0)	2,000,000	$ (0)	0
Credit Terms for Trade Receivables (Year)	30 years
Extended Credit Terms for Trade Receivables (Year)	60 years
Research and Development Expense	$ 3,863,000	4,238,000	$ 13,126,000	14,367,000
Customer Concentration Risk [Member] \| Accounts Receivable [Member]
Number of Major Customers			1
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Customer One [Member]
Accounts and Financing Receivable, after Allowance for Credit Loss	14,700,000		$ 14,700,000
Customer Concentration Risk [Member] \| Revenue from Contract with Customer Benchmark [Member] \| Customer One [Member]
Revenue from Contract with Customer, Including Assessed Tax	35,000	$ 0	14,200,000	$ 0
Subsidiaries [Member] \| Non-US [Member]
Cash and Cash Equivalent	$ 700,000		$ 700,000		$ 800,000

Credit terms for trade receivables.

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Represents the number of major customers accounting for 10% or more of the specified concentration risk benchmark, which includes, but not limited to, sales revenue, accounts receivable, etc.

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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 cash and cash equivalent. Cash includes, but is not limited to, currency on hand, demand deposit with financial institution, and account with general characteristic of demand deposit. Cash equivalent includes, but is not limited to, short-term, highly liquid investment that is both readily convertible to known amount of cash and so near maturity that it presents insignificant risk of change in value because of change in interest rate.

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Amount of expense for research and development. Includes, but is not limited to, cost for computer software product to be sold, leased, or otherwise marketed and writeoff of research and development assets acquired in transaction other than business combination or joint venture formation or both. Excludes write-down of intangible asset acquired in business combination or from joint venture formation or both, used in research and development activity.

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Amount of cash restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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