Note 5 - Net Income (Loss) Per Share - Basic and Diluted Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Weighted average common shares outstanding - basic (in shares)	40,788	40,275	40,723	39,143
Total effects of dilutive securities (in shares)	306	351	448	0
Shares used in dilutive earnings per share calculation (in shares)	41,094	40,626	41,171	39,143
Share-based Payment Arrangement, Option [Member]
Effect of dilutive securities (in shares)	306	351	448	0
Restricted Stock/Deferred Stock Units [Member]
Effect of dilutive securities (in shares)	0	0	0	0