Note 3 - Fair Value Measurement - Fair Value of Assets Measured on a Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Total cash and cash equivalents	$ 1,835	$ 7,363
Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	2	6,893
Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0	0
Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	0	0
Money Market Funds [Member]
Total cash and cash equivalents	2	6,893
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	2	6,893
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	0	0
Demand Deposits [Member]
Total cash and cash equivalents	223	470
Demand Deposits [Member] | Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	0	0
Demand Deposits [Member] | Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0	0
Demand Deposits [Member] | Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	0	$ 0
Savings Account [Member]
Total cash and cash equivalents	1,610
Savings Account [Member] | Fair Value, Inputs, Level 1 [Member]
Total cash and cash equivalents	0
Savings Account [Member] | Fair Value, Inputs, Level 2 [Member]
Total cash and cash equivalents	0
Savings Account [Member] | Fair Value, Inputs, Level 3 [Member]
Total cash and cash equivalents	$ 0