Note 3 - Marketable Securities - Summary of Unrealized Gains and Losses on Available-for-sale Securities (Details) - USD ($) $ in Thousands	Aug. 28, 2022	Feb. 27, 2022
Amortized cost basis	$ 103,514	$ 100,241
Gross unrealized gains	0	10
Gross unrealized losses	4,884	2,701
US Treasury and Government [Member]
Amortized cost basis	76,128	65,177
Gross unrealized gains	0	5
Gross unrealized losses	4,690	2,570
Debt Security, Corporate, US [Member]
Amortized cost basis	27,386	35,064
Gross unrealized gains	0	5
Gross unrealized losses	$ 194	$ 131

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).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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
-Name Accounting Standards Codification
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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
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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