Note 2 - Marketable Securities - Summary of Unrealized Gains and Losses on Available-for-sale Securities (Details) - USD ($) $ in Thousands	Mar. 01, 2020	Mar. 03, 2019
Amortized cost basis	$ 116,099	$ 80,651
Gross unrealized gains	846	51
Gross unrealized losses		85
US Treasury and Government [Member]
Amortized cost basis	100,626	68,727
Gross unrealized gains	764	44
Gross unrealized losses		53
Debt Security, Corporate, US [Member]
Amortized cost basis	15,473	11,924
Gross unrealized gains	82	7
Gross unrealized losses		$ 32