Consolidated Statements of Cash Flows (Parentheticals) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Series C Convertible Preferred Stock [Member]
Convertible preferred stock (in shares)	420	298	132
Conversion of stock, shares issued (in shares)	28,000,000	19,862,000	1,400,000
Series D Convertible Preferred Stock [Member]
Convertible preferred stock (in shares)	1,000
Conversion of stock, shares issued (in shares)	66,666,666