Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares outstanding (in shares)	111,542,108	111,757,105