Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Details)

v3.21.1
Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Assets:    
Total $ 323,801 $ 366,617
Level 1    
Assets:    
Total 144,596 286,061
Level 2    
Assets:    
Total 179,205 80,556
Money Market Funds    
Assets:    
Total 53,776 204,632
Money Market Funds | Level 1    
Assets:    
Total 53,776 204,632
Commercial Paper    
Assets:    
Total 64,344 42,208
Commercial Paper | Level 2    
Assets:    
Total 64,344 42,208
Corporate Debt Securities    
Assets:    
Total 64,678 25,716
Corporate Debt Securities | Level 2    
Assets:    
Total 64,678 25,716
Equity Securities    
Assets:    
Total 30,955 41,644
Equity Securities | Level 1    
Assets:    
Total 30,955 41,644
Asset-backed Securities    
Assets:    
Total 36,889 12,632
Asset-backed Securities | Level 2    
Assets:    
Total 36,889 12,632
U.S. Government Securities    
Assets:    
Total 59,865 39,785
U.S. Government Securities | Level 1    
Assets:    
Total 59,865 $ 39,785
Supranational Debt Securities    
Assets:    
Total 13,294  
Supranational Debt Securities | Level 2    
Assets:    
Total $ 13,294