Note 4 - Detail of Certain Asset Accounts (Details) - Intangible Assets (USD $)	9 Months Ended	12 Months Ended
Dec. 26, 2014	Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Carrying Value	$ 15,736,000	$ 15,461,000
Accumulated Amortization	13,058,000	12,519,000
Intangibles Net	2,678,000us-gaap_FiniteLivedIntangibleAssetsNet	2,942,000us-gaap_FiniteLivedIntangibleAssetsNet
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	122,000	113,000
Intangibles Net	68,000	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	1,394,000	1,267,000
Intangibles Net	876,000	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	10,851,000	10,672,000
Intangibles Net	99,000	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	39,000	23,000
Intangibles Net	109,000	125,000
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Carrying Value	729,000	795,000
Intangibles Net	729,000	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	1,449,000	1,108,000
Accumulated Amortization	652,000	444,000
Intangibles Net	$ 797,000	$ 664,000

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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Balance Type:	credit
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- Definition

The amortization method of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar either by their nature or by their use in the operations of a company. The straight-line method is the preferred amortization method, unless another method better reflects the pattern in which the asset is consumed.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 35

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=26713198&loc=d3e15372-109273

+ Details

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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Period Type:	instant

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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