Note 10 Employee Equity Incentive Plans (Share-based Compensation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based Compensation Effect on Income before Taxes	$ 2,867us-gaap_ShareBasedCompensation	$ 2,785us-gaap_ShareBasedCompensation	$ 3,451us-gaap_ShareBasedCompensation
Benefit from Income Taxes	1,009	1,071	1,287
Net Stock-based Compensation Effects on Net Income	1,858	1,714	2,164
Cost of Good Sold [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based Compensation Effect on Income before Taxes	433	457	398
Research, Development and Engineering [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based Compensation Effect on Income before Taxes	814	978	1,030
Selling, General and Administrative [[Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based Compensation Effect on Income before Taxes	$ 1,620	$ 1,350	$ 2,023

The amount of expense, net of income tax, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

No definition available.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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