Related Parties (Details)
$ in Thousands
1 Months Ended 12 Months Ended
Jun. 21, 2018
USD ($)
May 31, 2017
USD ($)
Apr. 30, 2017
USD ($)
item
Jan. 31, 2017
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2017
USD ($)
Related Parties              
Sublease income         $ 1,017 $ 908  
Maturity term from issuance date of the notes   7 years 7 years        
Maturity date of termination   60 days 60 days        
Interest rate (as a percent)     2.05%        
January 2017 promissory note              
Related Parties              
Amount due to related party             $ 0
Amount due from related party             0
Interest rate (as a percent)       1.97%      
May 2017 promissory note              
Related Parties              
Amount due to related party             0
Amount due from related party             0
Interest rate (as a percent)   2.04%          
Board of Directors Chairman              
Related Parties              
Loan receivable   $ 1,800   $ 700      
Principal amount of promissory note forgiven $ 2,500            
Interest on promissory note forgiven 100            
Executive officer              
Related Parties              
Amount due from related party             0
Principal balance of promissory note repaid 200            
Amount of promissory note received from early exercise of stock options     $ 200        
Number of promissory notes | item     2        
Number of restricted stock agreements | item     2        
Interest paid $ 100           $ 0