Accrued Expenses
 12 Months Ended
Dec. 31, 2021
Payables and Accruals [Abstract]  
Accrued Expenses
7. Accrued Expenses
Accrued expenses consisted of the following as of December 31, 2021 and 2020 (in thousands):
 
    
December 31,
2021
     
December 31,
2020
  
Selling and marketing costs
    $ 6,031      $ 3,468  
Employee compensation and related benefits
      2,005        1,090  
Professional fees
      225        73  
    
 
 
     
 
 
  
    
 
 
     
 
 
  
Total
    $ 8,261      $ 4,631