Note 12 - Commitments and Contingencies (Details Textual)	May 31, 2023	May 31, 2022
Entity Wide Trade Joint Venture Receivables, Two Joint Ventures, Percentage	65.10%
Entity Wide Trade, Joint Venture Receivables, One Joint Venture		62.30%

Percentage of total trade joint venture receivables accounted for by two joint ventures.

No definition available.

Name:	ntic_EntityWideTradeJointVentureReceivablesTwoJointVenturesPercentage
Namespace Prefix:	ntic_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant