Note 5 - Disaggregated Net Revenues and Segment Information - Net Revenue, Classified by Geography (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Net revenues	$ 830,821	$ 756,967
Chemical [Member]
Net revenues	387,632	359,171
Electronics [Member]
Net revenues	154,767	148,966
Engineering [Member]
Net revenues	288,422	248,830
UNITED STATES
Net revenues	705,449	655,002
UNITED STATES | Chemical [Member]
Net revenues	262,260	257,206
UNITED STATES | Electronics [Member]
Net revenues	154,767	148,966
UNITED STATES | Engineering [Member]
Net revenues	288,422	248,830
Non-US [Member]
Net revenues	125,372	101,965
Non-US [Member] | Chemical [Member]
Net revenues	125,372	101,965
Non-US [Member] | Electronics [Member]
Net revenues
Non-US [Member] | Engineering [Member]
Net revenues