Quarterly report pursuant to Section 13 or 15(d)

Note 7 - Fair Value Measurements and Financial Instruments - Assets Measured on a Recurring Basis (Details)

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Note 7 - Fair Value Measurements and Financial Instruments - Assets Measured on a Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2022
Dec. 31, 2021
Assets, fair value $ 61,817 $ 78,834
Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0 0
Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 61,817 78,834
Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Money Market Accounts [Member]    
Assets, fair value 215 17,974
Money Market Accounts [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0 0
Money Market Accounts [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 215 17,974
Money Market Accounts [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Money Market Funds [Member]    
Assets, fair value 26,736 15,801
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0 0
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 26,736 15,801
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Bank Time Deposits [Member]    
Assets, fair value 7,496 5,045
Bank Time Deposits [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0 0
Bank Time Deposits [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 7,496 5,045
Bank Time Deposits [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
United States Treasury Bill [Member]    
Assets, fair value 9,954  
United States Treasury Bill [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0  
United States Treasury Bill [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 9,954  
United States Treasury Bill [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0  
Commercial Notes [Member]    
Assets, fair value 12,421 19,998
Commercial Notes [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0 0
Commercial Notes [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 12,421 19,998
Commercial Notes [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0
Guaranteed Investment Certificate [Member]    
Assets, fair value   20,016
Guaranteed Investment Certificate [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value   0
Guaranteed Investment Certificate [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value   20,016
Guaranteed Investment Certificate [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value   $ 0
Canadian Provincial Commercial Notes [Member]    
Assets, fair value 4,995  
Canadian Provincial Commercial Notes [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value  
Canadian Provincial Commercial Notes [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 4,995  
Canadian Provincial Commercial Notes [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value