Note 5 - Disaggregated Net Revenues and Segment Information - Summary of Segment Information (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 830,821	$ 756,967
Segment operating income (loss)	69,285	17,096
Total assets	5,571,122		$ 4,545,092
Chemical [Member]
Revenue from Contract with Customer, Including Assessed Tax	387,632	359,171
Segment operating income (loss)	74,901	40,575
Total assets	2,618,427		1,985,501
Electronics [Member]
Revenue from Contract with Customer, Including Assessed Tax	154,767	148,966
Segment operating income (loss)	(56,860)	(62,843)
Total assets	947,091		1,099,983
Engineering [Member]
Revenue from Contract with Customer, Including Assessed Tax	288,422	248,830
Segment operating income (loss)	51,244	$ 39,364
Total assets	$ 2,005,604		$ 1,459,608