Note 6 - Income Taxes (Tables)

12 Months Ended

Mar. 31, 2020

Notes Tables

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

	Year Ended March 31
	2020			2019
Current taxes
Federal	$	2,710,658		$	3,107,376
State		(13,176	)		125,796
Deferred taxes
Federal		74,651			(30,012	)
State		3,128			(1,257	)
Income tax provision	$	2,775,261		$	3,201,903

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

	Year Ended March 31
	2020			2019
Tax expense at U.S. Statutory rate	$	3,633,400		$	3,719,066
State income taxes, net of Federal benefit		77,989			95,430
Research and development credits		(126,320	)		-
Foreign-derived intangible income deduction		(540,265	)		(555,256	)
Other		(269,543	)		(57,337	)
Income tax provision	$	2,775,261		$	3,201,903

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

	March 31
	2020			2019
Paid time off accrual	$	55,240		$	55,900
Inventory reserve		45,948			41,572
Depreciation and amortization		22,651			112,125
Stock-based compensation deductions		65,218			62,671
Unrealized (gain) loss on marketable securities		(144,668	)		23,170
Other		63,730			58,297
Deferred tax assets	$	108,119		$	353,735