Note 4 - Balance Sheet Components - Cash and Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Cash and cash equivalents	$ 28,698	$ 25,229
Gross unrealized gains	0	8
Gross unrealized losses	(7)	(4)
Short-term investments	13,240	26,494
Investments and Cash	41,945	51,719
Investments and Cash, Fair Value Disclosure	41,938	51,723
US Treasury Securities [Member]
Cash and cash equivalents	0	0
Amortized Cost	10,879	23,802
Gross unrealized gains	0	7
Gross unrealized losses	(7)	(4)
Estimated Fair Value	10,872	23,805
Short-term investments	10,872	23,805
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Cash and cash equivalents	0	0
Amortized Cost	2,368	2,688
Gross unrealized gains	0	1
Gross unrealized losses	0	0
Estimated Fair Value	2,368	2,689
Short-term investments	2,368	2,689
Cash [Member]
Cash and Cash Equivalents, at Carrying Value	3,912	8,740
Money market funds, Fair Value	3,912	8,740
Cash and cash equivalents	3,912	8,740
Money Market Funds [Member]
Cash and Cash Equivalents, at Carrying Value	24,786	16,489
Money market funds, Fair Value	24,786	16,489
Cash and cash equivalents	$ 24,786	$ 16,489