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Operating Segments - Customers (Details) - customer | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Concentration risk |  |  |  |
Number of customers | 23 | 17 | 25 | 18
Customer Concentration risk |  |  |  |
Concentration risk |  |  |  |
Number of customers | 4 | 3 | 2 | 3
Threshold concentration risk for reporting (as a percent) | 10.00% | 10.00% | 10.00% | 10.00%
Total Revenue | Customer Concentration risk | Customer One |  |  |  |
Concentration risk |  |  |  |
Concentration risk (as a percent) | 15.00% | 39.00% | 35.00% | 31.00%
Total Revenue | Customer Concentration risk | Customer Two |  |  |  |
Concentration risk |  |  |  |
Concentration risk (as a percent) | 14.00% | 28.00% | 10.00% | 21.00%
Total Revenue | Customer Concentration risk | Customer Three |  |  |  |
Concentration risk |  |  |  |
Concentration risk (as a percent) | 13.00% | 13.00% |  | 21.00%
Total Revenue | Customer Concentration risk | Customer Four |  |  |  |
Concentration risk |  |  |  |
Concentration risk (as a percent) | 11.00% |  |  |

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