Note 10 - Stockholders' Equity - Summary of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Outstanding (in shares)	859,975	846,754	931,840
Outstanding, weighted average exercise price (in dollars per share)	$ 37.53	$ 33.83	$ 28.22
Outstanding, weighted average contractual term (Year)	4 years 5 months 1 day	4 years 4 months 6 days	4 years 6 months	4 years 5 months 26 days
Outstanding, aggregate intrinsic value	$ 10,924	$ 7,878	$ 13,888	$ 11,442
Granted (in shares)	148,115	159,275	151,161
Granted, weighted average exercise price (in dollars per share)	$ 54.71	$ 47.21	$ 48.6
Exercised (in shares)	(207,643)	(133,963)	(217,121)
Exercised, weighted average exercise price (in dollars per share)	$ 29.72	$ 25.8	$ 20.95
Exercised, aggregate intrinsic value	$ 5,914	$ 3,021	$ 6,975
Canceled / Expired (in shares)	(19,323)	(12,091)	(19,126)
Canceled / Expired (in dollars per share)	$ 41.55	$ 35.53	$ 23.18
Outstanding (in shares)	781,124	859,975	846,754	931,840
Outstanding, weighted average exercise price (in dollars per share)	$ 42.78	$ 37.53	$ 33.83	$ 28.22
Exercisable (in shares)	356,519	369,593	301,692
Exercisable, weighted average exercise price (in dollars per share)	$ 36.83	$ 32.16	$ 27.4
Exercisable, weighted average contractual term (Year)	3 years 2 months 15 days	3 years 2 months 1 day	3 years 3 months 18 days
Exercisable, aggregate intrinsic value	$ 7,107	$ 5,223	$ 6,886
Expected to vest (in shares)	424,605	490,382	545,062
Expected to vest, weighted average exercise price (in dollars per share)	$ 47.78	$ 41.59	$ 37.38
Expected to vest, weighted average contractual term (Year)	5 years 5 months 4 days	5 years 2 months 23 days	5 years 1 month 28 days