Note 10 - Segment Information - Summary of Segment Information (Details) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 3,485,992	$ 3,018,954
Segment operating income (loss)	(43,389)	(374,720)
Total assets	5,053,089	4,545,092
Chemical [Member]
Revenue from Contract with Customer, Including Assessed Tax	1,368,365	1,318,814
Segment operating income (loss)	58,477	(81,849)
Total assets	505,389	1,985,501
Electronics [Member]
Revenue from Contract with Customer, Including Assessed Tax	1,400,918	730,634
Segment operating income (loss)	(147,023)	(403,099)
Total assets	1,970,705	1,099,983
Engineering [Member]
Revenue from Contract with Customer, Including Assessed Tax	716,709	969,506
Segment operating income (loss)	45,157	110,228
Total assets	$ 1,061,149	$ 1,459,608