Quarterly report pursuant to Section 13 or 15(d)

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

v3.21.1
Note 7 - Fair Value Measurements and Financial Instruments - Assets Measured on a Recurring Basis (Details) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Assets, fair value $ 111,478 $ 122,064
Fair Value, Inputs, Level 1 [Member]    
Assets, fair value
Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 111,478 122,064
Fair Value, Inputs, Level 3 [Member]    
Assets, fair value
Money Market Accounts [Member]    
Assets, fair value 1,232 668
Money Market Accounts [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value
Money Market Accounts [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 1,232 668
Money Market Accounts [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value
Money Market Funds [Member]    
Assets, fair value 40,001 44,000
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 40,001 44,000
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value
Bank Time Deposits [Member]    
Assets, fair value 45,246 48,397
Bank Time Deposits [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value
Bank Time Deposits [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 45,247 48,397
Bank Time Deposits [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value
US Treasury Securities [Member]    
Assets, fair value 5,000 5,000
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 5,000 5,000
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value
Canadian Treasury Securities [Member]    
Assets, fair value 19,999 23,999
Canadian Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]    
Assets, fair value
Canadian Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]    
Assets, fair value 19,999 23,999
Canadian Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]    
Assets, fair value