Unaudited Condensed Consolidated Balance Sheets (Parentheticals) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Unaudited Condensed Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares outstanding (in shares)	0	0
Preferred stock, shares Issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	260,000,000	260,000,000
Common stock, shares issued (in shares)	44,109,366	42,706,908
Common stock, shares outstanding (in shares)	44,109,366	42,706,908