Note 14 - Business Segments - Business Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Jun. 30, 2023
Revenues	$ 10,398	$ 9,842	$ 32,566	$ 34,171
Operating Income / (loss)	59	(37)	735	2,099
Assets	43,087	45,374	43,087	45,374	$ 42,186
Depreciation and amortization	760	1,498	3,546	3,641
Capital expenditures	50	83	208	4,077
Capital expenditures	760	1,498	3,546	3,641
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenues	0	0	0	0
Operating Income / (loss)	(255)	(87)	(41)	(276)
Assets	565	641	565	641
Depreciation and amortization	0	0	27	0
Capital expenditures		14	0	26
Capital expenditures	0	0	27	0
Manufacturing [Member]
Revenues	4,813	2,963	12,488	11,592
Manufacturing [Member] | Operating Segments [Member]
Revenues	4,813	2,963	12,488	11,592
Operating Income / (loss)	298	(104)	447	373
Assets	17,740	15,056	17,740	15,056
Depreciation and amortization	108	135	323	365
Capital expenditures	11	3	49	18
Capital expenditures	108	135	323	365
Testing Services [Member]
Revenues	3,796	5,697	13,606	17,709
Testing Services [Member] | Operating Segments [Member]
Revenues	3,796	5,697	13,606	17,709
Operating Income / (loss)	(183)	37	(463)	1,445
Assets	20,651	26,522	20,651	26,522
Depreciation and amortization	634	1,343	3,141	3,218
Capital expenditures	1	66	121	4,033
Capital expenditures	634	1,343	3,141	3,218
Distribution [Member]
Revenues	1,783	1,179	6,453	4,855
Distribution [Member] | Operating Segments [Member]
Revenues	1,783	1,179	6,453	4,855
Operating Income / (loss)	222	151	868	633
Assets	1,702	1,283	1,702	1,283
Depreciation and amortization	0	0	0	0
Capital expenditures	38	0	38	0
Capital expenditures	0	0	0	0
Real Estate Segment [Member]
Revenues	6	3	19	15
Real Estate Segment [Member] | Operating Segments [Member]
Revenues	6	3	19	15
Operating Income / (loss)	(23)	(34)	(76)	(76)
Assets	2,429	1,872	2,429	1,872
Depreciation and amortization	18	20	55	58
Capital expenditures	0	0	0	0
Capital expenditures	$ 18	$ 20	$ 55	$ 58