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v3.21.2

Concentrations of Credit Risk (Details) - item | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2021
Revenue | Customer | Customer 1 |  |
Concentrations of Credit Risk |  |
Number of major customers | 1 | 1

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- Definition Represents the number of major customers. + References No definition available. + Details
Name: | cert_NumberOfMajorCustomers
Namespace Prefix: | cert_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ConcentrationRiskLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_RevenueFromContractWithCustomerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | srt_MajorCustomersAxis=cert_Customer1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |