STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
OPERATING ACTIVITIES
Net income	$ 4,403,730	$ 4,140,116
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	59,457	87,621
Provision for current estimate of credit losses	212,440	0
Stock-based compensation	10,536	7,134
Deferred income taxes	(87,000)	1
Changes in operating assets and liabilities
Accounts receivable	913,872	1,191,613
Inventories	124,848	(455,402)
Prepaid expenses and other assets	(10,243)	(268,772)
Accounts payable and accrued expenses	(602,338)	(1,371,168)
Net cash provided by operating activities	5,025,302	3,331,143
INVESTING ACTIVITIES
Purchases of fixed assets	(4,131)	(24,500)
Purchases of marketable securities	(3,937,835)	(4,976,063)
Proceeds from maturities of marketable securities	3,400,000	9,250,000
Receipt of tenant improvement allowance	0	100,000
Net cash (used) provided by investing activities	(541,966)	4,349,437
FINANCING ACTIVITIES
Proceeds from exercise of stock options	117,527	0
Payment of dividends to shareholders	(4,830,826)	(4,830,826)
Cash used in financing activities	(4,713,299)	(4,830,826)
(Decrease) increase in cash and cash equivalents	(229,963)	2,849,754
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	1,439,933	13,299,264
Supplemental disclosures of cash flow information
Cash paid during the period for income taxes	$ 1,195,542	$ 1,275,629