Note 14 - Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
EARNINGS PER SHARE
Net income	$ (4,746)	$ (4,776)	$ 2,652	$ 1,963	$ 1,888	$ 5,550	$ 10,613	$ 6,883	$ (4,907)	$ 24,934	$ 25,074
Weighted average shares used to compute basic EPS (in shares)									42,460,000	40,838,000	40,039,000
Dilutive effect of stock-based awards (in shares)											224,000
Weighted average shares used to compute diluted EPS (in shares)									42,460,000	40,838,000	40,263,000
Basic (in dollars per share)	$ (0.11)	$ (0.11)	$ 0.06	$ 0.05	$ 0.05	$ 0.14	$ 0.26	$ 0.17	$ (0.12)	$ 0.61	$ 0.63
Diluted (in dollars per share)	$ (0.11)	$ (0.11)	$ 0.06	$ 0.05	$ 0.05	$ 0.14	$ 0.26	$ 0.17	$ (0.12)	$ 0.61	$ 0.62
Antidilutive shares									937,424	937,424