Note 4 - Detail of Certain Asset Accounts (Details) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended			12 Months Ended
	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014	Sep. 27, 2013	Mar. 31, 2014	Sep. 26, 2014 Patents [Member] Minimum [Member]	Sep. 26, 2014 Patents [Member] Maximum [Member]	Sep. 26, 2014 Patents [Member]	Mar. 31, 2014 Patents [Member]	Sep. 26, 2014 Other Intangible Assets [Member]	Mar. 31, 2014 Other Intangible Assets [Member]
Note 4 - Detail of Certain Asset Accounts (Details) [Line Items]
Amortization of Intangible Assets	$ 181,000	$ 259,000	$ 386,000	$ 509,000
Finite-Lived Intangible Asset, Useful Life						2 years	20 years	10 years	10 years
Finite-Lived Intangible Assets, Gross	$ 15,591,000		$ 15,591,000		$ 15,461,000			$ 1,391,000	$ 1,108,000	$ 642,000	$ 795,000