Note 10 - Major Customer and Vendor (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 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 four distributors represented 19%, 16%, 15% and 13% of total sales		sales through four distributors represented 17%, 17%, 13% and 13% of total sales	Sales to three distributors represented 21%, 15%, and 14% of total sales
Concentration Risk, Product	Sales of three products represented 50%, 10%, and 10% of total sales	Sales of three products represented 48%, 20%, and 16% of total sales	Sales of four products represented 43%, 14%, 10% and 10% of total sales	Sales of three products represented 50%, 17%, and 15% of total sales
ShandongYctMember
Concentration Risk, Supplier			49%	34%
OtherVendor1Member
Concentration Risk, Supplier			20%
OtherVendor2Member
Concentration Risk, Supplier			16%
OtherVendor3Member
Concentration Risk, Supplier				19%
OtherVendor4Member
Concentration Risk, Supplier				17%
OtherVendor5Member
Concentration Risk, Supplier				13%