Note 6 - Income Taxes (Tables)

12 Months Ended

Mar. 31, 2021

Notes Tables

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Year Ended March 31
	2021			2020
Current taxes
Federal	$	2,600,670		$	2,710,658
State		75,852			(13,176	)
Deferred taxes
Federal		(123,959	)		74,651
State		(5,195	)		3,128
Income tax provision	$	2,547,368		$	2,775,261

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year Ended March 31
	2021			2020
Tax expense at U.S. Statutory rate	$	2,990,768		$	3,633,400
State income taxes, net of Federal benefit		88,909			77,989
Research and development credits		(86,223	)		(126,320	)
Foreign-derived intangible income deduction		(450,912	)		(540,265	)
Other		4,826			(269,543	)
Income tax provision	$	2,547,368		$	2,775,261

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	March 31
	2021			2020
Paid time off accrual	$	60,869		$	55,240
Inventory reserve		50,324			45,948
Depreciation and amortization		88,690			22,651
Stock-based compensation deductions		75,189			65,218
Unrealized gain on marketable securities		(308,403	)		(144,668	)
Other		106,869			63,730
Deferred tax assets	$	73,538		$	108,119