Note 4 - Fair Value Measurements - Financial Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Marketable Securities	$ 83,239	$ 128,233
Corporate Debt Securities [Member]
Marketable Securities	44,963	54,281
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Marketable Securities	15,269	18,866
Certificates of Deposit [Member]
Marketable Securities	12,084	28,534
US Treasury Securities [Member]
Marketable Securities	6,524	10,472
Asset-Backed Securities [Member]
Marketable Securities	4,399	16,080
Fair Value, Recurring [Member]
Total assets	107,119	128,808
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Total assets	40,363	45,189
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Total assets	66,756	83,619
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Total assets	0	0
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Marketable Securities	44,963	54,281
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable Securities	44,963	54,281
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Marketable Securities	15,269	28,534
Fair Value, Recurring [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable Securities	0	28,534
Fair Value, Recurring [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable Securities	15,269	0
Fair Value, Recurring [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| Certificates of Deposit [Member]
Marketable Securities	12,084
Fair Value, Recurring [Member] \| Certificates of Deposit [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable Securities	12,084
Fair Value, Recurring [Member] \| Certificates of Deposit [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable Securities	0
Fair Value, Recurring [Member] \| Certificates of Deposit [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable Securities	0
Fair Value, Recurring [Member] \| US Treasury Securities [Member]
Marketable Securities	4,399	16,080
Fair Value, Recurring [Member] \| US Treasury Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable Securities	4,399	16,080
Fair Value, Recurring [Member] \| US Treasury Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| US Treasury Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable Securities	0
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member]
Marketable Securities	6,524	10,472
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable Securities	6,524	10,472
Fair Value, Recurring [Member] \| Asset-Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| Cash and Cash Equivalents [Member]
Marketable Securities	23,880	575
Fair Value, Recurring [Member] \| Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 1 [Member]
Marketable Securities	23,880	575
Fair Value, Recurring [Member] \| Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 2 [Member]
Marketable Securities	0	0
Fair Value, Recurring [Member] \| Cash and Cash Equivalents [Member] \| Fair Value, Inputs, Level 3 [Member]
Marketable Securities	$ 0	$ 0