Condensed Consolidated Balance Sheets (Parentheticals) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	18,275,577	18,224,577
Common stock, shares outstanding (in shares)	17,137,653	17,104,998
Treasury stock, shares (in shares)	1,137,924	1,119,579