Note 5 - Financial Instruments Measured at Fair Value - Effective Maturities of Short-term Investments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Due in one year or less, amortized cost	$ 112,956
Due in one year or less, fair value	112,683
Due after one year through three years, amortized cost	30,996
Due after one year through three years, fair value	30,552
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost, Total	143,952
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value, Total	$ 143,235