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Summary of Significant Accounting Policies (Details)
1 Months Ended 12 Months Ended
Feb. 29, 2020
shares
Dec. 31, 2020
USD ($)
segment
shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Class of Stock [Line Items]        
Number of operating segments (segment) | segment   1    
Restricted cash   $ 1,542,000 $ 0  
Allowance for credit loss   0 0  
Unrealized gains (losses)   (2,000) (1,000)  
Realized gains (losses) on investments   0 0  
Tangible asset impairment charges   0 0  
Unrecognized tax benefits, income tax penalties and interest expense   $ 0 $ 0 $ 0
Minimum        
Class of Stock [Line Items]        
Useful life (in years)   3 years    
Maximum        
Class of Stock [Line Items]        
Useful life (in years)   5 years    
Common Stock        
Class of Stock [Line Items]        
Shares issued as a result of conversion of promissory notes (in shares) | shares 24,385,388 24,385,388