Note 11 - Product Warranty - Changes in Product Warranty Liability (Details) - USD ($)	3 Months Ended	9 Months Ended
Aug. 31, 2025	Aug. 31, 2024	Aug. 31, 2025	Aug. 31, 2024
Balance	$ 213,929	$ 196,668	$ 225,186	$ 295,113
Provision charged to expense	77,334	71,426	260,709	250,102
Less amounts charged-off	(70,713)	(52,176)	(265,345)	(329,297)
Balance	$ 220,550	$ 215,918	$ 220,550	$ 215,918

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