Note 3 - Investments - Summary of Short-term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Investments, amortized cost	$ 14,932	$ 909
Investments, unrealized gains	4	0
Investments, unrealized losses	(15)	(15)
Investments, fair value	14,921	894
Investments, unrealized losses	15	15
Corporate Debt Securities [Member]
Investments, amortized cost	11,310	909
Investments, unrealized gains	0	0
Investments, unrealized losses	(15)	(15)
Investments, fair value	11,295	894
Investments, unrealized losses	15	$ 15
US Treasury and Government Short-Term Debt Securities [Member]
Investments, amortized cost	3,622
Investments, unrealized gains	4
Investments, unrealized losses	0
Investments, fair value	3,626
Investments, unrealized losses	$ 0

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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