Note 6 - Accrued Liabilities and Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accrued liabilities	$ 52,225	$ 41,806
Accrued compensation and related benefits	$ 14,600	$ 12,100
Annual occupational disease benefits discount rate	5.30%	5.60%
Estimated aggregate liability	$ 5,200	$ 3,600
Amount of occupational disease obligation	2,300	1,500
Contributions to defined contribution plan	3,100	2,300	$ 1,200
Restricted cash	800	900
Other long-term liabilities
Estimated aggregate liability	$ 3,100	$ 2,700