Note 5 - Stock-based Compensation - Summary of Share-based Compensation Cost (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share-Based Payment Arrangement, Expense	$ 672,000	$ 425,000	$ 1,145,000	$ 585,000
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense	622,000	425,000	1,095,000	585,000
General and Administrative Expense [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense	187,000	170,000	225,000	330,000
Research and Development Expense [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Expense	$ 435,000	$ 255,000	$ 870,000	$ 255,000