Note 4 - Detail of Certain Asset Accounts (Details) - Intangible Assets (USD $)	6 Months Ended	12 Months Ended
	Sep. 26, 2014	Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Carrying Value	$ 15,591,000	$ 15,461,000
Accumulated Amortization	12,905,000	12,519,000
Intangibles Net	2,686,000	2,942,000
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Lives in Years	15 years	15 years
Amortization Method	Straight Line	Straight Line
Carrying Value	190,000	190,000
Accumulated Amortization	119,000	113,000
Intangibles Net	71,000	77,000
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Lives in Years	15 years	15 years
Amortization Method	Cash Flow	Cash Flow
Carrying Value	2,270,000	2,270,000
Accumulated Amortization	1,352,000	1,267,000
Intangibles Net	918,000	1,003,000
Unpatented Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Lives in Years	10 years	10 years
Amortization Method	Cash Flow	Cash Flow
Carrying Value	10,950,000	10,950,000
Accumulated Amortization	10,791,000	10,672,000
Intangibles Net	159,000	278,000
Distribution Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Lives in Years	7 years	7 years
Amortization Method	Straight Line	Straight Line
Carrying Value	148,000	148,000
Accumulated Amortization	33,000	23,000
Intangibles Net	115,000	125,000
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Carrying Value	642,000	795,000
Intangibles Net	642,000	795,000
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Lives in Years	10 years	10 years
Amortization Method	Straight Line	Straight Line
Carrying Value	1,391,000	1,108,000
Accumulated Amortization	610,000	444,000
Intangibles Net	$ 781,000	$ 664,000