Note 5 - Disaggregated Revenues and Segment Information - Summary of Segment Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 956,791	$ 854,696	$ 1,787,612	$ 1,611,663
Segment operating income (loss)	(43,748)	86,455	25,537	103,551
Total assets	5,727,437		5,727,437		$ 4,545,092
Chemical [Member]
Revenue from Contract with Customer, Including Assessed Tax	412,649	427,697	800,281	786,868
Segment operating income (loss)	(42,634)	119,155	32,267	159,730
Total assets	2,577,346		2,577,346		1,985,501
Electronics [Member]
Revenue from Contract with Customer, Including Assessed Tax	281,210	99,740	435,977	248,706
Segment operating income (loss)	(29,524)	(84,067)	(86,384)	(146,909)
Total assets	1,317,311		1,317,311		1,099,983
Engineering [Member]
Revenue from Contract with Customer, Including Assessed Tax	262,932	327,259	551,354	576,089
Segment operating income (loss)	28,410	$ 51,367	79,654	$ 90,730
Total assets	$ 1,832,780		$ 1,832,780		$ 1,459,608