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Fair Value of Financial Instruments - Assets (Details) - Recurring - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Level 1    
Assets, Fair Value Disclosure [Abstract]    
Assets, Fair Value Disclosure   $ 0
Investments, Fair Value Disclosure [Abstract]    
Investments, Fair Value Disclosure $ 39,000  
Level 1 | Money Market Funds    
Assets, Fair Value Disclosure [Abstract]    
Cash and Cash Equivalents, Fair Value Disclosure 66,300  
Level 2    
Assets, Fair Value Disclosure [Abstract]    
Assets, Fair Value Disclosure 0 0
Level 3    
Assets, Fair Value Disclosure [Abstract]    
Assets, Fair Value Disclosure $ 0 $ 0