| Note 7 - Marketable Debt Securities (Details Textual) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 
|---|---|---|
| Aug. 31, 2025 | Aug. 31, 2025 | |
| Debt Securities, Unrealized Gain (Loss) | $ 0.1 | $ 0.1 | 
| Maximum [Member] | ||
| Debt Securities, Realized Gain (Loss) | $ 0.1 | $ 0.1 | 
| X | ||||||||||
| 
- Definition Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in net income (trading). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
 | 
| X | ||||||||||
| 
- Definition Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in net income (trading). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
 | 
| X | ||||||||||
| 
- Details 
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