Note 4 - Prepaid Expenses and Other - Prepaid Expenses and Other (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
CRO services	$ 340	$ 1,550
Other clinical development	2,933	2,718
Insurance	3,178	3,708
Professional fees	398	651
Other	2,135	2,635
Total, long-term	8,984	11,262
CRO services	166	518
Other clinical development	577	437
Other	611	790
Prepaid Expense and Other Assets, Noncurrent	1,354	1,745
Totals	$ 10,338	$ 13,007