Note 5 - Inventories - Summary of Inventories (Details) - USD ($)
Mar. 31, 2018
Mar. 31, 2017
Raw materials $ 1,084,030 $ 786,775
Work in process 1,828,492 1,968,990
Finished goods 737,917 602,533
Total inventories $ 3,650,439 $ 3,358,298