Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	600,000,000	600,000,000
Common stock, shares issued (in shares)	218,903,476	106,736,810
Common stock, shares outstanding (in shares)	218,903,476	106,736,810
Series B Convertible Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 1,000	$ 1,000
Preferred stock, shares issued (in shares)	100	100
Preferred stock, shares outstanding (in shares)	100	100
Series C Convertible Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 1,000	$ 1,000
Preferred stock, shares issued (in shares)	2,150	2,570
Preferred stock, shares outstanding (in shares)	2,150	2,570
Series D Convertible Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 1,000	$ 1,000
Preferred stock, shares issued (in shares)	0	1,000
Preferred stock, shares outstanding (in shares)	0	1,000
Series E Convertible Preferred Stock [Member]
Preferred stock, par value (in dollars per share)	$ 1,000	$ 1,000
Preferred stock, shares issued (in shares)	1,200	0
Preferred stock, shares outstanding (in shares)	1,200	0