Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Impairment of Long-Lived Assets Held-for-use	$ 0	$ 0	$ 0
Product Warranty Term	1 year
Depreciation, Depletion and Amortization	$ 1,147,451	850,970	934,371
Shipping, Handling and Transportation Costs	$ 12,760	$ 20,721	$ 12,771
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4,000	6,000	4,000
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	$ 0	$ 0	$ 0
Provision for Doubtful Accounts	0	0	0
Allowance for Doubtful Accounts Receivable, Write-offs	$ 0	$ 0	$ 0
Machinery and Equipment [Member]
Property, Plant and Equipment, Useful Life	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment, Useful Life	5 years