Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Accounts receivable, net of allowance for doubtful accounts	$ 5,000	$ 5,000
Mezzanine equity, liquidation preference	$ 22,965
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	2,000,000,000	2,000,000,000
Common stock, shares issued (in shares)	347,200,961	180,096,317
Common stock, shares outstanding (in shares)	347,194,257	180,089,613
Treasury stock, shares (in shares)	6,704	6,704
Mezzanine Equity [Member]
Mezzanine equity, par value (in dollars per share)	$ 0.01	$ 0.01
Mezzanine equity, shares authorized (in shares)	26,000	26,000
Mezzanine equity, shares issued (in shares)	23,611	22,863
Mezzanine equity, shares outstanding (in shares)	22,965	22,863
Mezzanine equity, liquidation preference	$ 22,965,000	$ 22,863,000
Series A Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	38,000	38,000
Preferred stock, shares issued (in shares)	37,467	37,467
Preferred stock, shares outstanding (in shares)	0	14,911
Preferred stock, liquidation preference	$ 0	$ 14,911,000
Series A-1 Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	38,000	38,000
Preferred stock, shares issued (in shares)	37,467	37,467
Preferred stock, shares outstanding (in shares)	0	14,782
Preferred stock, liquidation preference	$ 0	$ 14,782,000
Series B Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	750,000	750,000
Preferred stock, shares issued (in shares)	389,400	389,400
Preferred stock, shares outstanding (in shares)	239,400	239,400
Preferred stock, liquidation preference	$ 620,000	$ 608,000