Note 4 - Revenue Recognition 1 (Details Textual) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Revenue, Performance Obligation Satisfied, Revenue Recognized, Percentage	78.00%	72.00%
Geographic Concentration Risk [Member] \| Revenue Benchmark [Member] \| Non-US [Member]
Concentration Risk, Percentage	41.00%	51.00%
Minimum [Member]
Warranty Period (Year)	1 year
Contract with Customer, Payment Term (Day)	30 days
Maximum [Member]
Warranty Period (Year)	3 years
Extended Service Warranty, Term (Year)	4 years
Contract with Customer, Payment Term (Day)	60 days
Grant [Member]
Revenues, Total	$ 3.9	$ 6.4

Represents the payment term, from the date of delivery, under contracts with customers.

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- Definition

Represents the additional term of extended service-type warranties.

+ References

No definition available.

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- Definition

Represents the percentage of revenue recognized at the point of time when control transferred to the customer.

+ References

No definition available.

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- Definition

Represents the typical term of assurance-type warranties on all product sales.

+ References

No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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