STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
OPERATING ACTIVITIES
Net income	$ 22,694,458	$ 14,507,501
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	257,606	424,981
Stock-based compensation	59,657	81,855
Deferred income taxes	161,894	24,457
Changes in operating assets and liabilities
Accounts receivable	(1,818,515)	(2,740,548)
Inventories	(1,328,375)	(1,187,858)
Prepaid expenses and other assets	(208,532)	99,724
Accounts payable and accrued expenses	(726,695)	1,293,567
Net cash provided by operating activities	19,091,498	12,503,679
INVESTING ACTIVITIES
Purchases of fixed assets	(935,791)	(484,579)
Purchases of marketable securities	(28,441,317)	0
Proceeds from maturities of marketable securities	20,750,000	7,500,000
Receipt of tenant improvement allowance	100,000	0
Net cash (used in) provided by investing activities	(8,527,108)	7,015,421
FINANCING ACTIVITIES
Repurchase of common stock	(20,700)	(163,521)
Payment of dividends to shareholders	(19,323,304)	(19,333,409)
Net cash used in financing activities	(19,344,004)	(19,496,930)
(Decrease) increase in cash and cash equivalents	(8,779,614)	22,170
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance	10,449,510	10,427,340
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Ending Balance	1,669,896	10,449,510
Supplemental disclosures of cash flow information
Cash paid during the year for income taxes	$ 4,501,656	$ 2,520,000