Note 6 - Fair Value Measurements - Fair Value Assets by Investment Category (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Member]
Assets, fair value	$ 89,371	$ 70,266
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	31,188	0
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	639
Other Current Assets [Member]
Assets, fair value	3,293	101
Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	303	101
Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	2,990
Cash [Member] | Cash and Cash Equivalents [Member]
Assets, fair value	57,544	70,266
Cash [Member] | Other Current Assets [Member]
Assets, fair value	0	0
Money Market Funds [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	31,188	0
Money Market Funds [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	0	101
Money Market Funds, Rabbi Trust [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	0
Money Market Funds, Rabbi Trust [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	303
Certificates of Deposit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	639
Certificates of Deposit [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	2,990
Reported Value Measurement [Member]
Assets, fair value	92,664	70,367
Reported Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	31,491	101
Reported Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	3,629
Reported Value Measurement [Member] | Cash [Member]
Assets, fair value	57,544	70,266
Reported Value Measurement [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	31,188	101
Reported Value Measurement [Member] | Money Market Funds, Rabbi Trust [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	303
Reported Value Measurement [Member] | Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	3,629
Estimate of Fair Value Measurement [Member]
Assets, fair value	92,961	70,367
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	31,491	101
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	3,926
Estimate of Fair Value Measurement [Member] | Cash [Member]
Assets, fair value	57,544	70,266
Estimate of Fair Value Measurement [Member] | Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	31,188	$ 101
Estimate of Fair Value Measurement [Member] | Money Market Funds, Rabbi Trust [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	303
Estimate of Fair Value Measurement [Member] | Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	$ 3,926