Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock, par value (in dollars per share)	$ 0
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	45,152,000	40,444,000
Common stock, shares outstanding (in shares)	45,152,000	40,444,000