Note 3 - Income Taxes - Deferred Income Taxes (Details) - USD ($)	Sep. 30, 2022	Sep. 30, 2021
Deferred tax assets attributable to:
Accrued liabilities, including supplemental compensation and vacation pay accrual	$ 1,792,000	$ 1,603,000
Impairment losses on marketable securities	(182,000)	(113,000)
Impairment losses on marketable securities	182,000	113,000
Bad debt reserves not yet deductible	56,000	55,000
Depreciation and amortization	2,686,000	3,065,000
Deferred revenues	1,316,000	1,836,000
Goodwill	451,000	520,000
Net operating losses	657,000	561,000
Credits and other	71,000	268,000
Total deferred tax assets	6,847,000	8,021,000
Unrealized gains on marketable securities	(32,120,000)	(64,115,000)
Net deferred income taxes	$ (25,273,000)	$ (56,094,000)