Intangible Assets that Have Definite Lives (Detail) (USD $)	9 Months Ended	12 Months Ended
Dec. 28, 2012	Mar. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Carrying Value	$ 14,945,000	$ 15,132,000
Accumulated Amortization	11,185,000	10,594,000
Intangibles Net	3,760,000	4,538,000
Customer list
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	475,000
Accumulated Amortization	97,000	372,000
Intangibles Net	93,000	103,000
Trademarks
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	1,066,000	949,000
Intangibles Net	1,204,000	1,321,000
Technology
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	9,716,000	9,027,000
Intangibles Net	1,234,000	1,923,000
Patents pending
Finite-Lived Intangible Assets [Line Items]
Carrying Value	676,000	673,000
Intangibles Net	676,000	673,000
Patents
Finite-Lived Intangible Assets [Line Items]
Weighted Average Lives in Years	10 years	10 years
Amortization Method	Straight Line	Straight Line
Carrying Value	859,000	764,000
Accumulated Amortization	306,000	246,000
Intangibles Net	$ 553,000	$ 518,000

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=7658586&loc=d3e16323-109275

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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 Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 12, 13, 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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=7658317&loc=d3e15372-109273

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	debit
Period Type:	instant

- Details

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Period Type:	duration

- 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.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph ((a)(1),(b))

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 42, 45

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant