v3.21.2
Summary of Significant Accounting Policies - Contract Balances and Accounts Receivable (Details) - USD ($)
9 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Accounting Policies [Abstract]      
Provision for expected credit losses, contract balances $ 100,000 $ 200,000  
Writeoffs, contract balances 0   $ 0
Allowance for credit loss, contract balances 300,000   300,000
Unbilled receivables 3,700,000   2,100,000
Provision for expected credit losses, accounts receivable 200,000 $ 1,000,000  
Writeoffs, accounts receivable 100,000   600,000
Allowance reserve 600,000   600,000
Allowance for credit losses, sales credits $ 600,000   $ 500,000