Note 6 - Inventories - Summary of Inventories (Details) - USD ($)	Dec. 31, 2020	Mar. 31, 2020
Raw materials	$ 839,102	$ 1,017,451
Work in process	1,959,692	1,863,000
Finished goods	1,043,683	1,003,999
Total inventories	$ 3,842,477	$ 3,884,450	[1]

[1] The March 31, 2020 Balance Sheet is derived from the audited financial statements contained in our Annual Report on Form 10-K for the fiscal year ended March 31, 2020.