Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Jun. 30, 2019	Mar. 31, 2019
Accounts receivable, allowance for doubtful accounts	$ 160,000	$ 160,000
Property and equipment, accumulated depreciation	117,475	108,099
Intangible assets, accumulated amortization	$ 12,384	$ 12,035
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0005	$ 0.0005
Common stock, authorized (in shares)	150,000,000	150,000,000
Common stock, issued (in shares)	67,588,492	67,588,492
Common stock, outstanding (in shares)	67,588,492	67,588,492