Note 16 - Stock Based Compensation - Options Outstanding (Details)	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Options outstanding (in shares) | shares	5,332,775
Options outstanding, weighted-average exercise price (in dollars per share)	$ 5.50
Options exercisable, shares (in shares) | shares	3,689,035
Options exercisable, weighted-average exercise price (in dollars per share)	$ 5.90
Range 1 [Member]
Lower range limit (in dollars per share)	1.90
Upper range limit (in dollars per share)	$ 3.53
Options outstanding (in shares) | shares	1,482,675
Options outstanding, weighted-average remaining contractual life (Year)	6 years 4 months 24 days
Options outstanding, weighted-average exercise price (in dollars per share)	$ 2.85
Options exercisable, shares (in shares) | shares	511,923
Options exercisable, weighted-average exercise price (in dollars per share)	$ 2.61
Range 2 [Member]
Lower range limit (in dollars per share)	3.55
Upper range limit (in dollars per share)	$ 3.94
Options outstanding (in shares) | shares	559,850
Options outstanding, weighted-average remaining contractual life (Year)	2 years 9 months 18 days
Options outstanding, weighted-average exercise price (in dollars per share)	$ 3.60
Options exercisable, shares (in shares) | shares	557,850
Options exercisable, weighted-average exercise price (in dollars per share)	$ 3.60
Range 3 [Member]
Lower range limit (in dollars per share)	3.99
Upper range limit (in dollars per share)	$ 7.85
Options outstanding (in shares) | shares	1,585,625
Options outstanding, weighted-average remaining contractual life (Year)	6 years 2 months 12 days
Options outstanding, weighted-average exercise price (in dollars per share)	$ 5.73
Options exercisable, shares (in shares) | shares	1,128,625
Options exercisable, weighted-average exercise price (in dollars per share)	$ 5.52
Range 4 [Member]
Lower range limit (in dollars per share)	8.00
Upper range limit (in dollars per share)	$ 9.45
Options outstanding (in shares) | shares	1,704,625
Options outstanding, weighted-average remaining contractual life (Year)	5 years 7 months 6 days
Options outstanding, weighted-average exercise price (in dollars per share)	$ 8.22
Options exercisable, shares (in shares) | shares	1,490,637
Options exercisable, weighted-average exercise price (in dollars per share)	$ 8.19