Note 1 - Summary of Significant Accounting Policies - Option Activity (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) $ / shares shares
Outstanding (in shares) | shares	387,500
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 4.57
Granted (in shares) | shares	74,000
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 10.73
Exercised (in shares) | shares	(10,000)
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 3.43
Cancelled (in shares) | shares	(600)
Cancelled, weighted average exercise price (in dollars per share) | $ / shares	$ 3.29
Outstanding (in shares) | shares	450,900
Outstanding, weighted average exercise price (in dollars per share) | $ / shares	$ 5.58
Outstanding, weighted average remaining contractual term (Year)	7 years 1 month 13 days
Outstanding, aggregate intrinsic value | $	$ 2,063
Exercisable (in shares) | shares	204,500
Exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 3.92
Exercisable, weighted average remaining contractual term (Year)	6 years 3 months 25 days
Exercisable, aggregate intrinsic value | $	$ 889