Note 11 - Net Income (Loss) Per Common Share - Calculation of Diluted Shares (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net income (loss)	$ 7,876	$ (16,380)	$ 6,758	$ 5,928
Amount attributable to unvested restricted shares	0	0	(7)	(674)
Amount attributable to warrants outstanding	(215)	0	(208)	(161)
Net income (loss) allocated to common shareholders	$ 7,661	$ (16,380)	$ 6,543	$ 5,093
Weighted-average common shares issued and outstanding (in shares)	38,072,712	23,292,635	35,668,124	22,151,726
Basic earnings (loss) per common share (in dollars per share)	$ 0.20	$ (0.70)	$ 0.18	$ 0.23
Amount attributable to unvested restricted shares	$ 208	$ (0)	$ 200	$ (0)
Amount attributable to warrants	(0)	(0)	7	106
Less: gain related to change in fair value of warrants	(0)	(0)	(0)	5,472
Diluted earnings (loss) allocated to common shareholders	$ 7,668	$ (16,380)	$ 6,551	$ 350
Stock options (in shares)	1,249,810	0	1,436,767	1,717,253
Restricted shares (in shares)	1,067,576	0	1,134,003	237,234
Warrants (in shares)	0	0	36,709	2,907,367
Diluted weighted average shares issued and outstanding (in shares)	40,390,098	23,292,635	38,275,603	27,013,580
Diluted earnings (loss) per common share (in dollars per share)	$ 0.19	$ (0.70)	$ 0.17	$ 0.01