Statements of Cash Flows - USD ($)	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
OPERATING ACTIVITIES
Net income	$ 14,507,501	$ 11,694,384
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	424,981	542,926
Stock-based compensation	81,855	45,572
Deferred income taxes	24,457	(129,155)
Changes in operating assets and liabilities:
Accounts receivable	(2,740,548)	729,737
Inventories	(1,187,858)	(16,327)
Prepaid expenses and other assets	99,724	391,699
Accounts payable and accrued expenses	1,293,567	105,996
Net cash provided by operating activities	12,503,679	13,364,832
INVESTING ACTIVITIES
Purchases of fixed assets	(484,579)	(62,727)
Purchases of marketable securities	0	(10,512,400)
Proceeds from maturities and sales of marketable securities	7,500,000	19,000,000
Net cash provided by investing activities	7,015,421	8,424,873
FINANCING ACTIVITIES
Repurchase of common stock	(163,521)	(91,419)
Payment of dividends to shareholders	(19,333,409)	(19,336,540)
Net cash used in financing activities	(19,496,930)	(19,427,959)
Increase in cash and cash equivalents	22,170	2,361,746
Cash and cash equivalents at beginning of year	10,427,340	8,065,594
Cash and cash equivalents at end of year	10,449,510	10,427,340
Supplemental disclosures of cash flow information:
Cash paid during the year for income taxes	$ 2,520,000	$ 2,438,788