Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Accounts Receivable, Credit Loss Expense (Reversal)	$ 0	$ 0
Product Warranty Term (Year)		1 year
Impairment of Long-Lived Assets Held-for-use	0	$ 0
Depreciation, Depletion and Amortization, Nonproduction, Total	$ 308,511	$ 364,409
Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment, Useful Life (Year)	5 years

Represents product warranty term.

No definition available.

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- Definition

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
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- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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- Definition

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(5))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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