Note 3 - Summary of Significant Accounting Policies (Details Textual) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 $ / shares	Jan. 01, 2021 USD ($)
Number of Operating Segments	1
Cash and Cash Equivalents, at Carrying Value, Total	$ 34,946	$ 144,514
Impairment, Long-Lived Asset, Held-for-Use, Total	0	0
Operating Lease, Right-of-Use Asset	2,967	$ 4,089
Operating Lease, Liability, Total	$ 2,935
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset				$ 5,100
Operating Lease, Liability, Total				$ 5,100
Common Stock [Member]
Shares Issued, Price Per Share (in dollars per share) | $ / shares			$ 5.00