Note 5 - Disaggregated Revenues and Segment Information - Summary of Segment Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 805,126	$ 739,538	$ 2,592,738	$ 2,351,201
Segment operating income	(65,724)	(219,922)	(40,187)	(116,371)
Total assets	5,269,834		5,269,834		$ 4,545,092
Chemical [Member]
Revenue from Contract with Customer, Including Assessed Tax	295,262	281,431	1,095,543	1,068,299
Segment operating income	68,392	(70,274)	100,659	89,456
Total assets	2,266,028		2,266,028		1,985,501
Electronics [Member]
Revenue from Contract with Customer, Including Assessed Tax	430,114	181,779	866,091	430,486
Segment operating income	(114,589)	(166,740)	(200,973)	(313,649)
Total assets	1,686,347		1,686,347		1,099,983
Engineering [Member]
Revenue from Contract with Customer, Including Assessed Tax	79,750	276,328	631,104	852,416
Segment operating income	(19,527)	$ 17,092	60,127	$ 107,822
Total assets	$ 1,317,459		$ 1,317,459		$ 1,459,608