Quarterly report pursuant to Section 13 or 15(d)

Note 5 - Cash, Cash Equivalents and Investments - Cash Equivalents and Investments Carried at Fair Value (Details)

v3.23.3
Note 5 - Cash, Cash Equivalents and Investments - Cash Equivalents and Investments Carried at Fair Value (Details) - USD ($)
$ in Thousands
Sep. 30, 2023
Dec. 31, 2022
Fair Value $ 11,916  
Total 39,569 $ 38,152
Fair Value, Inputs, Level 1 [Member]    
Total 39,569 22,087
Fair Value, Inputs, Level 2 [Member]    
Total 0 16,065
Fair Value, Inputs, Level 3 [Member]    
Total 0 0
Money Market Funds [Member]    
Money market funds, included in cash equivalents 27,653 17,618
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]    
Money market funds, included in cash equivalents 27,653 17,618
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]    
Money market funds, included in cash equivalents 0 0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]    
Money market funds, included in cash equivalents 0 0
US Treasury Securities [Member]    
Fair Value 11,916 3,573
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair Value 11,916 3,573
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value 0 0
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Fair Value $ 0 0
Debt Security, Government, Non-US [Member]    
Fair Value   896
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair Value   896
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value   0
Debt Security, Government, Non-US [Member] | Fair Value, Inputs, Level 3 [Member]    
Fair Value   0
Asset-Backed Securities [Member]    
Fair Value   499
Asset-Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair Value   0
Asset-Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value   499
Asset-Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Fair Value   0
Corporate Bond Securities [Member]    
Fair Value   15,566
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair Value   0
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value   15,566
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Fair Value   $ 0