Consolidated Balance Sheets (Parentheticals) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	9,042	9,042
Preferred stock, shares outstanding (in shares)	9,042	9,042
Preferred stock, liquidation preference, value	$ 93,627,392	$ 98,243,690
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	550,000,000	550,000,000
Common stock, shares issued (in shares)	171,656,039	166,392,479
Common stock, shares outstanding (in shares)	169,556,403	165,932,334
Treasury shares (in shares)	2,099,636	460,145