Annual report pursuant to Section 13 and 15(d)

Note 4 - Marketable Securities - Fair Value of Marketable Securities (Details)

v3.22.0.1
Note 4 - Marketable Securities - Fair Value of Marketable Securities (Details) - Fair Value, Recurring [Member] - USD ($)
$ in Thousands
Dec. 31, 2021
Dec. 31, 2020
Total marketable securities $ 40,405 $ 20,098
Fair Value, Inputs, Level 1 [Member]    
Total marketable securities 0 0
Fair Value, Inputs, Level 2 [Member]    
Total marketable securities 40,405 20,098
Fair Value, Inputs, Level 3 [Member]    
Total marketable securities 0 0
Commercial Paper and Corporate Bonds [Member]    
Total marketable securities 29,421 10,678
Commercial Paper and Corporate Bonds [Member] | Fair Value, Inputs, Level 1 [Member]    
Total marketable securities 0 0
Commercial Paper and Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member]    
Total marketable securities 29,421 10,678
Commercial Paper and Corporate Bonds [Member] | Fair Value, Inputs, Level 3 [Member]    
Total marketable securities 0 0
US Government Agencies Debt Securities [Member]    
Total marketable securities 10,984 8,924
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Total marketable securities 0 0
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Total marketable securities 10,984 8,924
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Total marketable securities $ 0 0
Bank Certificates of Deposit [Member]    
Total marketable securities   496
Bank Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]    
Total marketable securities   0
Bank Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]    
Total marketable securities   496
Bank Certificates of Deposit [Member] | Fair Value, Inputs, Level 3 [Member]    
Total marketable securities   $ 0