Note 4 - Fair Value of Financial Instruments (Tables)

9 Months Ended

Jun. 30, 2025

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	As of June 30, 2025
	(Level 1)		(Level 2)		(Level 3)		Totals
Short-term investments:
Corporate bonds	$	—	$	1,997	$	—	$	1,997

	As of September 30, 2024
	(Level 1)		(Level 2)		(Level 3)		Totals
Recurring:
Short-term investments:
Corporate bonds	$	—	$	21,849	$	—	$	21,849
U.S. treasury securities and securities of U.S. government-sponsored agency		—		8,378		—		8,378
Total	$	—	$	30,227	$	—	$	30,227
Nonrecurring:
Note receivable on sale of subsidiary	$	—	$	—	$	2,600	$	2,600