Note 3 - Marketable Securities - Summary of Unrealized Gains and Losses on Available-for-sale Securities (Details) - USD ($) $ in Thousands	May 30, 2021	Feb. 28, 2021
Amortized cost basis	$ 77,909	$ 75,408
Gross unrealized gains	160	205
Gross unrealized losses	550	666
US Treasury and Government [Member]
Amortized cost basis	60,814	57,400
Gross unrealized gains	119	153
Gross unrealized losses	538	647
Debt Security, Corporate, US [Member]
Amortized cost basis	17,095	18,008
Gross unrealized gains	41	52
Gross unrealized losses	$ 12	$ 19

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Section 50
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Publisher FASB
-Name Accounting Standards Codification
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