Note 9 - Stock Repurchase Program (Details Textual) - Repurchase Program 2009 [Member] - USD ($)	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Aug. 27, 2015	Jan. 21, 2009
Stock Repurchase Program, Authorized Amount				$ 2,500,000
Stock Repurchase Program Authorized Additional Amount			$ 5,000,000
Stock Repurchased During Period, Shares (in shares)	1,806	12,972
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 3,762,040

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration