Note 2 - Marketable Securities - Summary of Unrealized Gains and Losses on Available-for-sale Securities (Details) - USD ($) $ in Thousands	Feb. 27, 2022	Feb. 28, 2021
Amortized cost basis	$ 100,241	$ 75,408
Gross unrealized gains	10	205
Gross unrealized losses	2,701	666
US Treasury and Government [Member]
Amortized cost basis	65,177	57,400
Gross unrealized gains	5	153
Gross unrealized losses	2,570	647
Debt Security, Corporate, US [Member]
Amortized cost basis	35,064	18,008
Gross unrealized gains	5	52
Gross unrealized losses	$ 131	$ 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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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).

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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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