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v3.21.2

Summary of Significant Accounting Policies - Concentration (Details) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2021 customer USD ($) | Sep. 30, 2020 USD ($) | Dec. 31, 2020 customer
Sales | Customer |  |  |
Risk and Uncertainties |  |  |
Number of customers exceeding 10% of benchmark | $ | 0 | 0 |
Accounts receivable | Credit |  |  |
Risk and Uncertainties |  |  |
Number of customers exceeding 10% of benchmark | customer | 0 |  | 0

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