Note 5 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2021	Jun. 30, 2023	Sep. 30, 2022
Operating Lease, Right-of-Use Asset		$ 383	$ 651
General and Administrative Expense [Member]
Operating Lease, Expense		400
Office in Novato, California [Member]
Lessee, Operating Lease, Renewal Term (Year)	3 years
Operating Lease, Right-of-Use Asset	$ 1,100
Lease Expiration Date	Jul. 31, 2024
Other Long-term Operating Leases [Member]
Contractual Obligation		$ 0	$ 0