Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Details)

v3.20.4
Fair Value Measurements (Details) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Non-marketable debt securities $ 1,000,000 $ 0
Total 128,567,000  
Investment in non-marketable equity securities   0
Convertible Debt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Non-marketable debt securities 1,000,000 0
Debt Securities, Available-for-sale, Unrealized Loss 0  
Debt Securities, Available-for-sale, Allowance for Credit Loss, Writeoff 0  
Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Estimated Fair Value 127,567,000 71,248,000
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total 127,567,000  
Level 1 | Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Estimated Fair Value 127,567,000 $ 71,248,000
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Non-marketable debt securities 1,000,000  
Total $ 1,000,000