Note 3 - Marketable Securities (Details) - Fair Value Of Available-For-Sale Securities (USD $) In Thousands, unless otherwise specified	Sep. 01, 2013	Mar. 03, 2013
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	$ 174,189	$ 89,099
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	144,294	58,299
US Treasury and Government [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	144,294	58,299
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	22,825	20,859
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	7,070	9,941
Corporate Debt Securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	29,895	30,800
Fair Value, Inputs, Level 1 [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	167,119	79,158
Fair Value, Inputs, Level 2 [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Available-for-sale securities	$ 7,070	$ 9,941