Note 7 - Net Income (Loss) Per Share - Calculations of Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Basic:
Net income (loss)	$ (3,164)	$ 483	$ (6,709)	$ 18,333	$ (320)	$ 17,625	$ (9,390)	$ 35,638
Basic (in shares)	16,281			20,786			16,405	20,847
Basic (in dollars per share)	$ (0.19)			$ 0.88			$ (0.57)	$ 1.71
Diluted:
Net income (loss)	$ (3,164)	$ 483	$ (6,709)	$ 18,333	$ (320)	$ 17,625	$ (9,390)	$ 35,638
Basic (in shares)	16,281			20,786			16,405	20,847
Unvested restricted stock and DSU's (in shares)	0			0			0	0
Employee stock options (in shares)	0			0			0	0
Diluted (in shares)	16,281			20,786			16,405	20,847
Diluted (in dollars per share)	$ (0.19)			$ 0.88			$ (0.57)	$ 1.71