Note 5 - Fair Value Measurements - Debt Securities by Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Due within one year, amortized cost	$ 79,998
Due within one year, unrealized gain	2,358
Due within one year, unrealized losses	0
Due within one year, fair value	82,356
Due within one and two years, amortized cost	34,907
Due within one and two years, unrealized gain	0
Due within one and two years, unrealized losses	(40)
Due within one and two years, fair value	34,867
Total, amortized cost	114,905
Total, unrealized gain	2,358
Total, unrealized losses	(40)
Total, fair value	$ 117,223