CONDENSED CONSOLIDATED INCOME STATEMENTS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Net sales	$ 11,282	$ 10,173	$ 22,369	$ 20,161
Cost of sales	8,659	6,769	16,791	13,329
Gross profit	2,623	3,404	5,578	6,832
Operating expenses:
Selling expenses	68	22	122	59
General and administrative expenses	951	1,165	1,975	2,257
Research and development costs	467	615	1,395	1,596
Total operating expenses	1,486	1,802	3,492	3,912
Operating income	1,137	1,602	2,086	2,920
Interest expense	(128)	(117)	(258)	(237)
Unrealized gain (loss) on marketable equity investments	158	(300)	408	(152)
Interest and other income	7	25	225	49
Gain on sale of investments			7
Income before income taxes	1,174	1,210	2,468	2,580
Income tax expense	(295)	(285)	(513)	(592)
Net income	$ 879	$ 925	$ 1,955	$ 1,988
Basic net income per share:
Net income	$ 0.25	$ 0.25	$ 0.54	$ 0.54
Diluted net income per share:
Net income	$ 0.24	$ 0.25	$ 0.53	$ 0.53
Basic	3,574	3,657	3,595	3,654
Diluted	3,652	3,767	3,672	3,774
Common shares outstanding	3,554	3,642	3,554	3,642