Note 4 - Stock-based Compensation - Summary of Option Activity (Details) - USD ($)			12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Options outstanding, weighted average contractual ife (Year)	7 years
Options outstanding, aggregate intrinsic value	$ 29,978		$ 29,978
Options granted (in shares)			0
Granted, weighted average exercise price (in dollars per share)			$ 0
Options granted, weighted average grant date fair value (in dollars per share)			$ 0
Options exercised (in shares)			(15)
Exercised, weighted average exercise price (in dollars per share)			$ 15.77
Options exercised, weighted average grant date fair value (in dollars per share)			$ 4.9
Options forfeited (in shares)			0
Forfeited, weighted average exercise price (in dollars per share)			$ 0
Options forfeited, weighted average grant date fair value (in dollars per share)			$ 0
Options outstanding, aggregate intrinsic value	$ (29,978)		$ (29,978)
Options outstanding, weighted average grant date fair value (in dollars per share)	$ 8.43		$ 8.43
Balance (in shares)	1,072		1,072
Options outstanding, weighted average exercise price (in dollars per share)	$ 18.07		$ 18.07
Share-Based Payment Arrangement, Option [Member]
Balance (in shares)			1,087	1,111	721
Options outstanding, weighted average exercise price (in dollars per share)			$ 18.04	$ 17.99	$ 15.77
Options outstanding, weighted average grant date fair value (in dollars per share)			$ 8.39	$ 8.31	$ 7.26
Options outstanding, weighted average contractual ife (Year)		8 years			9 years	9 years 9 months 18 days
Options outstanding, aggregate intrinsic value		$ 17,968,000		$ 17,968,000	$ (9,382,000)	$ (692,000)
Options granted (in shares)				0	450
Granted, weighted average exercise price (in dollars per share)				$ 0	$ 21.24
Options granted, weighted average grant date fair value (in dollars per share)				$ 0	$ 9.85
Options exercised (in shares)				(24)	0
Exercised, weighted average exercise price (in dollars per share)				$ 15.77	$ 0
Options exercised, weighted average grant date fair value (in dollars per share)				$ 4.9	$ 0
Options forfeited (in shares)				0	(60)
Forfeited, weighted average exercise price (in dollars per share)				$ 0	$ 15.77
Options forfeited, weighted average grant date fair value (in dollars per share)				$ 0	$ 7.26
Options outstanding, aggregate intrinsic value		$ (17,968,000)		$ (17,968,000)	$ 9,382,000	$ 692,000
Options outstanding, weighted average grant date fair value (in dollars per share)		$ 8.39		$ 8.39	$ 8.31	$ 7.26
Balance (in shares)		1,087		1,087	1,111	721
Options outstanding, weighted average exercise price (in dollars per share)		$ 18.04		$ 18.04	$ 17.99	$ 15.77
Exercisable (in shares)	238		238
Exercisable, weighted average exercise price (in dollars per share)	$ 18.35		$ 18.35
Exercisable, weighted average grant date fair value (in dollars per share)	$ 5.52		$ 5.52
Exercisable, weighted average contractual life (Year)	7 years 1 month 6 days
Exercisable, options outstanding, aggregate intrinsic valueo	$ 6,600,000		$ 6,600,000