Note 5 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Income Tax Examination, Penalties and Interest Accrued, Total	$ 0		$ 0		$ 0
Income Tax Examination, Penalties and Interest Expense, Total	$ 0	$ 0	$ 0	$ 0

The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

Name:	us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant