Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Accounts receivable, allowance for doubtful accounts	$ 278,000	$ 419,000
Inventories, reserves	399,000	258,000
Debt discount
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	350,000,000	350,000,000
Common stock, shares issued (in shares)	2,704,837	2,168,337
Common stock, shares outstanding (in shares)	2,704,837	2,168,337
Convertible Promissory Note [Member]
Debt discount	$ 5,781,000	$ 6,026,000