Note 2 - Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Retained Earnings (Accumulated Deficit), Total	$ (144,100)	$ (144,105)	$ (140,604)
Cash and Cash Equivalents, at Carrying Value, Total	4,900	$ 4,857	$ 7,363
Cash, Uninsured Amount	$ 4,500