Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, non-convertible shares authorized (in shares)	60,000,000	60,000,000
Common Stock, shares issued (in shares)	38,452,111	37,446,323
Common stock, shares outstanding (in shares)	38,452,111	37,446,323