Note 3 - Marketable Securities - Summary of Unrealized Gains and Losses on Available-for-sale Securities (Details) - USD ($) $ in Thousands	Nov. 29, 2020	Mar. 01, 2020
Amortized cost basis	$ 112,833	$ 116,099
Gross unrealized gains	571	846
Gross unrealized losses	227
US Treasury and Government [Member]
Amortized cost basis	92,783	100,626
Gross unrealized gains	497	764
Gross unrealized losses	209
Debt Security, Corporate, US [Member]
Amortized cost basis	20,050	15,473
Gross unrealized gains	74	82
Gross unrealized losses	$ 18

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).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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