Note 9 - Product Warranty - Changes in Product Warranty Liability (Details) - USD ($)	3 Months Ended	9 Months Ended
Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2022	Aug. 31, 2021
Balance, beginning	$ 89,549	$ 267,500	$ 202,850	$ 291,453
Settlements / adjustments	(69,721)	(75,204)	(277,734)	(177,470)
Warranties issued	136,999	53,384	231,711	131,697
Balance, ending	$ 156,827	$ 245,680	$ 156,827	$ 245,680

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1),(c)(5)
-URI https://asc.fasb.org/extlink&oid=126907703&loc=d3e12565-110249

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