Note 9 - Product Warranty - Changes In Product Warranty Liability (Details) - USD ($)	12 Months Ended
Nov. 30, 2017	Nov. 30, 2016
Balance, beginning	$ 134,373	$ 176,531
Settlements / adjustments	(276,667)	(246,235)
Warranties issued	210,745	204,077
Balance, ending	$ 68,451	$ 134,373

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/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1),(c)(5)
-URI http://asc.fasb.org/extlink&oid=68068213&loc=d3e12565-110249

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