Note 5 - Segment Information - Summary of Segment Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Revenues	$ 1,021,042	$ 1,156,512	$ 3,237,103	$ 3,914,281
Segment operating income (loss)	15,653	(39,910)	395,002	909,597
Total assets	4,473,850		4,473,850		$ 4,520,649
Chemical [Member]
Revenues	432,803	288,083	1,051,914	942,931
Segment operating income (loss)	25,646	27,225	88,622	128,440
Total assets	1,453,802		1,453,802		1,110,111
Electronics [Member]
Revenues	123,685	410,784	960,442	1,347,857
Segment operating income (loss)	22,111	(9,544)	95,172	369,414
Total assets	1,327,382		1,327,382		1,553,484
Engineering [Member]
Revenues	464,554	457,645	1,224,747	1,623,493
Segment operating income (loss)	(32,104)	$ (57,591)	211,208	$ 411,743
Total assets	$ 1,692,666		$ 1,692,666		$ 1,857,054