Note 9 - Product Warranty - Changes in Product Warranty Liability (Details) - USD ($)	3 Months Ended	6 Months Ended
May 31, 2023	May 31, 2022	May 31, 2023	May 31, 2022
Balance, beginning	$ 194,464	$ 115,062	$ 193,301	$ 202,850
Settlements / adjustments	115,739	73,088	(231,335)	(94,712)
Provision charged to expense	(115,739)	(73,088)	231,335	94,712
Warranties issued	(56,759)	(98,601)	(171,192)	(208,013)
Less amounts charged-off	(56,759)	(98,601)	(171,192)	(208,013)
Balance, ending	$ 253,444	$ 89,549	$ 253,444	$ 89,549

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482425/460-10-50-8

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (c)(5)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482425/460-10-50-8

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