Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities:
Net loss	$ (419,535)	$ (257,609)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Recovery of credit losses		(4,105)
Depreciation of equipment and leasehold improvements	53,133	45,614
Accretion of discount on treasury securities	(75,821)	(120,305)
Noncash operating lease expense	1,917	1,917
Stock-based compensation expense	14,264	46,792
Change in cash surrender value of life insurance	(165,291)	(149,057)
Provision (benefit) for deferred compensation	197,374	(59,935)
Net changes in operating assets and liabilities:
Accounts receivable	(180,291)	52,498
Inventories	(261,430)	644,569
Prepaid expenses and other current assets	(80,096)	(178,041)
Interest receivable	55,814	(5,243)
Income taxes receivable	(2,529)	(40,462)
Income taxes payable	(7,674)	(85,358)
Accounts payable	401,865	(38,968)
Accrued liabilities	650,248	(542,689)
Deferred revenue	19,606	(22,865)
Net cash provided by (used in) operating activities	201,554	(713,247)
Investing activities:
Purchase of equipment and leasehold improvements	(357,193)	(312,718)
Life insurance premiums paid	(70,577)	(81,744)
Proceeds from the maturity of treasury securities	5,034,000	2,000,000
Purchases of treasury securities	(4,999,003)	(1,999,074)
Net cash used in investing activities	(392,773)	(393,536)
Financing activities:
Proceeds from exercise of stock options	104,870
Net cash provided by financing activities	104,870
Net (decrease) in cash and cash equivalents	(86,349)	(1,106,783)
Cash and cash equivalents at beginning of period	2,837,081	3,091,062
Cash and cash equivalents at end of period	2,750,732	1,984,279
Supplemental cash flow information:
Cash paid for income taxes	$ 12,963	$ 127,700