Note 3 - Marketable Securities - Summary of Unrealized Gains/Losses on Available-for-Sale Securities (Details) - USD ($)	9 Months Ended	12 Months Ended
	Nov. 29, 2015	Mar. 01, 2015
US Treasury and Government [Member]
Amortized Cost Basis	$ 125,093,000	$ 119,191,000
Gross Unrealized Gains	209,000	314,000
Gross Unrealized Losses	156,000	12,000
Domestic Corporate Debt Securities [Member]
Amortized Cost Basis	27,836,000	11,097,000
Gross Unrealized Gains	0	5,000
Gross Unrealized Losses	74,000	0
Amortized Cost Basis	152,929,000	130,288,000
Gross Unrealized Gains	209,000	319,000
Gross Unrealized Losses	$ 230,000	$ 12,000