Note 8 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accruals	$ 1,218	$ 1,502
Net operating loss carryforwards	66,952	61,072
Tax credit carryforwards	10,838	9,815
Stock-based compensation	9,588	7,704
R&D capitalization	10,358	7,384
Lease liability	1,869	1,920
Property and equipment	35	7
Intangible assets	279	99
Gross deferred tax assets	101,137	89,503
Valuation allowance	(99,542)	(87,853)
Total deferred tax assets	1,595	1,650
Right-of-use assets	(1,595)	(1,650)
Total deferred tax liabilities	(1,595)	(1,650)
Net deferred tax assets/(liabilities)	$ 0	$ 0