Note 11 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accruals	$ 1,502	$ 3,404
Net operating loss carryforwards	61,072	56,447
Tax credit carryforwards	9,815	7,111
Stock-based compensation	7,704	8,784
R&D capitalization	7,384	3,810
Lease liability	1,920	2,948
Fixed assets	(7)	0
Intangibles	(99)	0
Gross deferred tax assets	89,503	82,504
Valuation allowance	(87,853)	(79,779)
Total deferred tax assets	1,650	2,725
Intangibles	0	(117)
Right-of-use asset	(1,650)	(2,593)
Fixed assets	0	(15)
Total deferred tax liabilities	(1,650)	(2,725)
Net deferred tax assets/(liabilities)	$ 0	$ 0