Consolidated Statements of Stockholders' Equity (Parentheticals) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement of Stockholders' Equity [Abstract]
Issuance of treasury stock (in shares)	100	100
Issuance of treasury stock, stock option exercise (in shares)	4,892	14,680
Repurchase of common stock through stock repurchase program (in shares)	63,844	1,498,202