Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Total stock-based compensation expense	$ 13,586	$ 7,181
Time-based Options [Member]
Total stock-based compensation expense	10,343	3,827
Performance-based Options [Member]
Total stock-based compensation expense	38	1,977
Market-based Options [Member]
Total stock-based compensation expense	2,926	1,130
Employee Stock Purchase Plan Award [Member]
Total stock-based compensation expense	279	247
Research and Development Expense [Member]
Total stock-based compensation expense	6,293	3,491
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 7,293	$ 3,690