CONDENSED CONSOLIDATED INCOME STATEMENTS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Net sales	$ 9,265	$ 11,739	$ 29,426	$ 28,594
Cost of sales	6,407	7,354	19,737	18,138
Gross profit	2,858	4,385	9,689	10,456
Operating expenses:
Selling expenses	20	136	79	415
General and administrative expenses	1,145	1,280	3,402	2,922
Loss on disposal of equipment	14		14
Research and development costs	658	1,104	2,254	3,184
Total operating expenses	1,837	2,520	5,749	6,521
Operating income	1,021	1,865	3,940	3,935
Interest expense	(112)	(102)	(349)	(231)
Unrealized gain (loss) on marketable equity investments	(275)	136	(427)	1,442
Interest and other income		41	50	102
Gain on sale of investments		783		795
Income before income taxes	634	2,723	3,214	6,043
Income tax expense	(172)	(592)	(764)	(1,004)
Net income	$ 462	$ 2,131	$ 2,450	$ 5,039
Basic net income per share:
Net income	$ 0.13	$ 0.56	$ 0.67	$ 1.31
Diluted net income per share:
Net income	$ 0.12	$ 0.54	$ 0.65	$ 1.26
Weighted average common shares outstanding:
Basic	3,626	3,817	3,645	3,843
Diluted	3,749	3,966	3,774	3,998
Common shares outstanding	3,618	3,701	3,618	3,701