Note 6 - Disaggregated Revenues and Segment Information - Summary of Segment Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2023
Net revenues	$ 754,132	$ 1,140,268	$ 1,516,821	$ 2,061,676
Segment operating income	(227,650)	102,892	(365,446)	68,267
Total assets	2,742,022		2,742,022		$ 3,089,825
Chemical [Member]
Net revenues	282,910	345,395	620,915	717,570
Segment operating income	(115,567)	1,018	(195,355)	12,411
Total assets	1,124,229		1,124,229		1,050,541
Electronics [Member]
Net revenues	392,878	633,857	681,307	1,098,549
Segment operating income	(102,070)	43,226	(153,512)	(23,429)
Total assets	1,233,910		1,233,910		1,575,811
Engineering [Member]
Net revenues	78,344	161,016	214,599	245,557
Segment operating income	(10,013)	$ 58,648	(16,579)	$ 79,285
Total assets	$ 383,883		$ 383,883		$ 463,473