Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Narrative (Details)

v3.21.2
Long-Term Debt - Narrative (Details)
1 Months Ended 9 Months Ended 12 Months Ended
Aug. 31, 2021
USD ($)
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
payment
Dec. 31, 2019
USD ($)
Jan. 31, 2019
USD ($)
Debt Instrument [Line Items]            
Proceeds from line of credit   $ 5,995,000 $ 0      
Revolving credit facility            
Debt Instrument [Line Items]            
Outstanding balance   $ 10,000,000        
Silicon Valley Bank Note            
Debt Instrument [Line Items]            
Note payable       $ 4,000,000 $ 4,000,000  
Number of required principal payments | payment       36    
Amount of required principal payment       $ 100,000    
Note payable converted into deemed advance the line of credit $ 4,000,000          
Silicon Valley Bank Line of Credit | Revolving credit facility            
Debt Instrument [Line Items]            
Borrowing capacity 50,000,000         $ 10,000,000
Proceeds from line of credit 6,000,000          
Outstanding balance $ 10,000,000          
Frequency of debt agreement fee annual          
Debt agreement fee $ 100,000          
Unused line fee (percent) 0.15%          
Debt covenant, outstanding principal balance threshold $ 10,000,000          
Debt covenant, minimum unrestricted cash and cash equivalents 100,000,000          
Debt covenant, minimum consolidated liquidity $ 20,000,000          
Silicon Valley Bank Line of Credit | Revolving credit facility | Minimum            
Debt Instrument [Line Items]            
Interest rate, minimum (percent) 3.50%          
Silicon Valley Bank Line of Credit | Revolving credit facility | Prime rate            
Debt Instrument [Line Items]            
Basis spread on variable rate (percent) 0.25%