CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
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)	37,561,744	37,446,323
Common stock, shares outstanding (in shares)	37,561,744	37,446,323