Note 10 - Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
EARNINGS PER SHARE
Net income	$ (4,776)	$ 2,652	$ 1,962	$ 5,550	$ 10,613	$ 6,883	$ (162)	$ 23,046
Weighted average shares used to compute basic EPS (in shares)	42,647			40,936			42,373	40,804
Weighted average shares used to compute diluted EPS (in shares)	42,647			40,936			42,373	40,804
Basic (in dollars per share)	$ (0.11)			$ 0.14			$ 0.00	$ 0.56
Diluted (in dollars per share)	$ (0.11)			$ 0.14			$ 0.00	$ 0.56
Antidilutive shares	937,424