Note 5 - Disaggregated Revenues and Segment Information - Net Revenue, Classified by Geography (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net revenues	$ 956,791	$ 854,696	$ 1,787,612	$ 1,611,663
Chemical [Member]
Net revenues	412,649	427,697	800,281	786,868
Electronics [Member]
Net revenues	281,210	99,740	435,977	248,706
Engineering [Member]
Net revenues	262,932	327,259	551,354	576,089
UNITED STATES
Net revenues	839,881	709,719	1,545,330	1,364,124
UNITED STATES | Chemical [Member]
Net revenues	295,739	307,708	557,999	564,317
UNITED STATES | Electronics [Member]
Net revenues	281,210	74,752	435,977	223,718
UNITED STATES | Engineering [Member]
Net revenues	262,932	327,259	551,354	576,089
Non-US [Member]
Net revenues	116,910	144,977	242,282	247,539
Non-US [Member] | Chemical [Member]
Net revenues	116,910	119,989	242,282	222,551
Non-US [Member] | Electronics [Member]
Net revenues		24,988		24,988
Non-US [Member] | Engineering [Member]
Net revenues