Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.2
Note 7 - Fair Value Measurements and Financial Instruments - Assets Measured on a Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2021
Dec. 31, 2020
Assets, fair value $ 102,578 $ 122,064
Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0 0
Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 102,578 122,064
Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Money Market Accounts [Member]    
Assets, fair value 207 668
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 207 668
Money Market Accounts [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Money Market Funds [Member]    
Assets, fair value 38,501 44,000
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 38,501 44,000
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Bank Time Deposits [Member]    
Assets, fair value 43,871 48,397
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 43,871 48,397
Bank Time Deposits [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value 0 0
Corporate Debt Securities [Member]    
Assets, fair value 19,999  
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value 0  
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 19,999  
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value $ 0  
US Treasury Securities [Member]    
Assets, fair value   5,000
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value   0
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value   5,000
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value   0
Canadian Treasury Securities [Member]    
Assets, fair value   23,999
Canadian Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value   0
Canadian Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value   23,999
Canadian Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value   $ 0