Note 9 - 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																12 Months Ended
	Dec. 31, 2022		Sep. 30, 2022		Jun. 30, 2022		Mar. 31, 2022		Dec. 31, 2021		Sep. 30, 2021		Jun. 30, 2021		Mar. 31, 2021		Dec. 31, 2022	Dec. 31, 2021
Basic:
Net income (loss)	$ (4,873)		$ (3,164)		$ 483		$ (6,709)		$ (8,634)		$ 18,333		$ (320)		$ 17,625		$ (14,263)	$ 27,004
Basic (in shares)																	16,337	19,827
Basic (in dollars per share)	$ (0.30)	[1]	$ (0.19)	[1]	$ 0.03	[1]	$ (0.40)	[1]	$ (0.51)	[1]	$ 0.88	[1]	$ (0.02)	[1]	$ 0.84	[1]	$ (0.87)	$ 1.36
Diluted:
Net income (loss)	$ (4,873)		$ (3,164)		$ 483		$ (6,709)		$ (8,634)		$ 18,333		$ (320)		$ 17,625		$ (14,263)	$ 27,004
Diluted (in shares)																	16,337	19,827
Diluted (in dollars per share)	$ (0.30)	[1]	$ (0.19)	[1]	$ 0.03	[1]	$ (0.40)	[1]	$ (0.51)	[1]	$ 0.88	[1]	$ (0.02)	[1]	$ 0.84	[1]	$ (0.87)	$ 1.36

[1] Per share amounts for the quarters have each been calculated separately. Accordingly, quarterly amounts may not add to the annual amounts because of differences in the average common shares outstanding during each period. Additionally, in regard to diluted per share amounts only, quarterly amounts may not add to the annual amounts because of the inclusion of the effect of potentially dilutive securities only in the periods in which such effect would have been dilutive, and because of the adjustments to net income (loss) for the dilutive effect of common stock equivalents and convertible securities at our ownership interests.