Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE MEASUREMENTS - Assets measured on recurring basis (Details)

v3.21.2
FAIR VALUE MEASUREMENTS - Assets measured on recurring basis (Details) - USD ($)
 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Assets      
Total liabilities $ 6,558,000    
Level 1 to Level 2 transfer 0 $ 0  
Level 2 to Level 1 transfer 0 0  
Transfer into Level 3 0 0  
Transfer out of Level 3 0 $ 0  
Level 3      
Assets      
Total liabilities 6,558,000    
Movement in Level 3 assets measured at fair value      
Balance at beginning of year 3,000,000    
Additions 3,620,000    
Changes in fair value 517,000    
Balance at end of year 7,137,000    
Movement in Level 3 liabilities measured at fair value      
Balance at beginning of period 93,328,000    
Additions 6,558,000    
Changes in fair value 56,576,000    
Exercise of private placement warrants (149,904,000)    
Balance at end of period 6,558,000    
Recurring      
Assets      
Total assets 514,453,000   $ 597,753,000
Total liabilities     93,328,000
Recurring | Contingent Consideration      
Assets      
Total liabilities 6,084,000    
Recurring | Subscription Agreement      
Assets      
Total liabilities 474,000    
Recurring | Private Placement Warrants      
Assets      
Total liabilities     93,328,000
Recurring | Money market funds      
Assets      
Total assets 180,998,000   407,512,000
Recurring | Commercial paper      
Assets      
Total assets 159,591,000   119,285,000
Recurring | Corporate bonds      
Assets      
Total assets 104,755,000   47,959,000
Recurring | Government bonds      
Assets      
Total assets 36,727,000    
Recurring | Assetbacked securities      
Assets      
Total assets 25,245,000    
Recurring | Other investments      
Assets      
Total assets 7,137,000   3,000,000
Recurring | U.S Treasury securities      
Assets      
Total assets     19,997,000
Recurring | Level 1      
Assets      
Total assets 180,998,000   427,509,000
Recurring | Level 1 | Money market funds      
Assets      
Total assets 180,998,000   407,512,000
Recurring | Level 1 | U.S Treasury securities      
Assets      
Total assets     19,997,000
Recurring | Level 2      
Assets      
Total assets 326,318,000   167,244,000
Recurring | Level 2 | Commercial paper      
Assets      
Total assets 159,591,000   119,285,000
Recurring | Level 2 | Corporate bonds      
Assets      
Total assets 104,755,000   47,959,000
Recurring | Level 2 | Government bonds      
Assets      
Total assets 36,727,000    
Recurring | Level 2 | Assetbacked securities      
Assets      
Total assets 25,245,000    
Recurring | Level 3      
Assets      
Total assets 7,137,000   3,000,000
Total liabilities     93,328,000
Recurring | Level 3 | Contingent Consideration      
Assets      
Total liabilities 6,084,000    
Recurring | Level 3 | Subscription Agreement      
Assets      
Total liabilities 474,000    
Recurring | Level 3 | Private Placement Warrants      
Assets      
Total liabilities     93,328,000
Recurring | Level 3 | Other investments      
Assets      
Total assets $ 7,137,000   $ 3,000,000