Note 3 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Restricted cash held as a certificate of deposit	$ 477	$ 476
Warrant liabilities		334
Fair Value, Inputs, Level 1 [Member]
Restricted cash held as a certificate of deposit	477	476
Warrant liabilities		0
Fair Value, Inputs, Level 2 [Member]
Restricted cash held as a certificate of deposit	0	0
Warrant liabilities		334
Fair Value, Inputs, Level 3 [Member]
Restricted cash held as a certificate of deposit	$ 0	0
Warrant liabilities		$ 0