Note 10 - Major Customer and Vendor (Details)	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Number Of Major Distributors	The Company sold products through ten distributors	The Company sold products through ten distributors	The Company sold products through ten distributors	The Company sold products through ten distributors
Concentration Risk, Other Risk	Sales to five distributors represented 17%, 14%, 12%, 11%, and 11% of total sales	and sales to three distributors represented 19%, 15%, and 12% of total sales	sales through four distributors represented 17%, 16%, 13%, and 12% of total sales	Sales to three distributors represented 20%, 15%, and 13% of total sales
Concentration Risk, Product	Sales of two products represented 38% and 24% of total sales	Sales of three products represented 46%, 20%, and 14% of total sales	Sales of three products represented 41%, 17% and 10% of total sales	Sales of three products represented 48%, 17%, and 16% of total sales
Shandong YCT
Concentration Risk, Supplier			42%	32%
Other Vendor 1
Concentration Risk, Supplier			25%
Other Vendor 2
Concentration Risk, Supplier			14%
Other Vendor 3
Concentration Risk, Supplier				25%
Other Vendor 4
Concentration Risk, Supplier				17%