STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	9 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
OPERATING ACTIVITIES
Net income	$ 13,311,718	$ 14,461,814
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	156,073	187,781
Provision for current estimate of credit losses	9,514	0
Stock-based compensation	129,392	54,218
Deferred income taxes	(847,235)	(61,972)
Changes in operating assets and liabilities
Accounts receivable	4,268,102	2,607,555
Inventories	(932,801)	(1,370,592)
Prepaid expenses and other assets	167,546	(502,423)
Accounts payable and accrued expenses	(1,147,278)	(627,470)
Net cash provided by operating activities	15,115,031	14,748,911
INVESTING ACTIVITIES
Purchases of fixed assets	(16,731)	(907,612)
Purchases of marketable securities	(6,103,185)	(26,618,617)
Proceeds from maturities of marketable securities	8,400,000	18,750,000
Receipt of tenant improvement allowance	0	100,000
Net cash provided (used) by investing activities	2,280,084	(8,676,229)
FINANCING ACTIVITIES
Proceeds from exercise of stock options	117,527	0
Payment of dividends to shareholders	(14,497,628)	(14,492,478)
Cash used in financing activities	(14,380,101)	(14,492,478)
Increase (decrease) in cash and cash equivalents	3,015,014	(8,419,796)
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance	1,669,896	10,449,510
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Ending Balance	4,684,910	2,029,714
Supplemental disclosures of cash flow information
Cash paid during the period for income taxes	$ 3,685,861	$ 4,130,278