Note 4 - Fair Value Measurements - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Business Combination, Contingent Consideration, Liability, Current	$ 4,315	$ 4,315
Estimate of Fair Value Measurement [Member]
Business Combination, Contingent Consideration, Liability, Current	4,315	4,315
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Business Combination, Contingent Consideration, Liability, Current	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Business Combination, Contingent Consideration, Liability, Current	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Business Combination, Contingent Consideration, Liability, Current	4,315	4,315
Reported Value Measurement [Member]
Business Combination, Contingent Consideration, Liability, Current	0	0
Money Market Funds [Member] | Estimate of Fair Value Measurement [Member]
Cash equivalents	67,112	67,046
Money Market Funds [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents	67,112	67,046
Money Market Funds [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents	0	0
Money Market Funds [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents	0	0
Money Market Funds [Member] | Reported Value Measurement [Member]
Cash equivalents	$ 67,112	$ 67,046