CONDENSED CONSOLIDATED INCOME STATEMENTS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Net sales	$ 11,087	$ 9,988
Cost of sales	8,131	6,560
Gross profit	2,956	3,428
Operating expenses:
Selling expenses	53	37
General and administrative expenses	1,024	1,093
Research and development costs	929	980
Total operating expenses	2,006	2,110
Operating income	950	1,318
Other income (expense):
Interest and dividend income	218	24
Realized gain on sale of marketable equity investments	6
Unrealized gain on marketable equity investments	250	149
Interest expense	(130)	(120)
Total other income	344	53
Income before income taxes	1,294	1,371
Provision for income taxes	218	307
Net income	$ 1,076	$ 1,064
Basic net income per share	$ 0.30	$ 0.29
Diluted net income per share	$ 0.29	$ 0.28
Basic	3,616,392	3,651,334
Diluted	3,694,959	3,777,118
Common shares outstanding	3,606,422	3,666,319