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Fair Value Measurements (Tables)
3 Months Ended
Mar. 31, 2022
Fair Value Disclosures [Abstract]  
Schedule of assets and liabilities that are measured at fair value
   March 31, 2022 
   Fair Value   Level 1   Level 2   Level 3 
Cash equivalents:                
Money market funds  $16,016   $16,016   $
   $
 
Total cash equivalents  $16,016   $16,016   $   $ 
                     
Short-term investments:                    
Certificates of deposit  $249   $   $249   $ 
Commercial paper   548        548     
Corporate notes   7,998        7,998     
Municipal bonds   452        452     
Total short-term investments  $9,247   $   $9,247   $ 

   December 31, 2021 
   Fair Value   Level 1   Level 2   Level 3 
                 
Cash equivalents:                
Money market funds  $16,830   $16,830   $
   $
 
Total cash equivalents  $16,830   $16,830   $
   $
 
                     
Short-term investments:                    
Certificates of deposit  $250   $
   $250   $
 
Commercial paper   2,210    
    2,210    
 
Corporate notes   12,024    
    12,024    
 
Municipal bonds   1,437    
    1,437    
 
Total short-term investments  $15,921   $
   $15,921   $