Note 13 - Stock-based Compensation - Summary of Option Activity (Details) - Lindblad Plan and 2015 Plan [Member] - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Options outstanding, shares (in shares)	510,000	200,000	220,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 10.30	$ 9.47	$ 3.23
Options outstanding, weighted average contractual ife (Year)	8 years 9 months 18 days	6 years 8 months 12 days	7 years 7 months 6 days	7 years 7 months 6 days
Options outstanding, aggregate intrinsic value	$ 1,848,040	$ 3,476,800	$ 1,376,000	$ 842,000
Exercised, shares (in shares)	(12,000)		(20,000)
Exercised, weighted average exercise price (in dollars per share)	$ 9.47		$ 11.26
Granted, shares (in shares)	1,000,000	310,000
Granted, weighted average exercise price (in dollars per share)	$ 16.38	$ 10.84
Options outstanding, shares (in shares)	1,498,000	510,000	200,000	220,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 14.37	$ 10.30	$ 9.47	$ 3.23
Options vested and/or expected to vest, number of options (in shares)	1,498,000
Options vested and/or expected to vest, weighted average exercise price (in dollars per share)	$ 14.37
Options vested and/or expected to vest, weighted average contractual life (Year)	8 years 9 months 18 days
Options vested and/or expected to vest, aggregate intrinsic value	$ 1,848,040
Options exercisable, number of options (in shares)	265,500
Options exercisable, weighted average exercise price (in dollars per share)	$ 9.87
Options exercisable, weighted average contractual life (Year)	6 years
Options exercisable, aggregate intrinsic value	$ 1,521,340