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)

v3.23.1
Note 5 - Cash, Cash Equivalents and Investments - Cash Equivalents and Investments Carried at Fair Value (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Fair value $ 8,637  
Total 35,646 $ 38,152
Fair Value, Inputs, Level 1 [Member]    
Total 29,386 22,087
Fair Value, Inputs, Level 2 [Member]    
Total 6,260 16,065
Fair Value, Inputs, Level 3 [Member]    
Total 0 0
Money Market Funds [Member]    
Money market funds, included in cash equivalents 27,009 17,618
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]    
Money market funds, included in cash equivalents 27,009 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 2,377 3,573
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair value 2,377 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
Corporate Bond Securities [Member]    
Fair value 6,260 15,566
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Fair value 0 0
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair value 6,260 15,566
Corporate Bond 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