Note 15 - Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Federal and state net operating losses	$ 79,856	$ 77,201
Federal and state research and experimentation credits	13,610	12,406
Research and experimental costs	12,806	9,458
Stock based compensation	1,822	1,474
ASC 842 - lease liabilities	1,303	1,468
Accrued compensation	324	610
Fixed asset differences	191	185
Intangible asset differences	4	0
Other	264	59
Total gross deferred tax assets	110,180	102,861
Less valuation allowance	(104,361)	(95,256)
Net deferred tax assets	5,819	7,605
Deferred tax liabilities:
Patent expenditures	(888)	(1,096)
ASC 842 - right of use assets	(795)	(897)
Fixed asset differences	(4)	(9)
Intangible asset differences	(4,132)	(5,603)
Total gross deferred tax liabilities	(5,819)	(7,605)
Total net deferred tax assets and liabilities	$ 0	$ 0