XML 50 R40.htm IDEA: XBRL DOCUMENT
v3.21.1

Fair Value Measurements - Summary of Common Stock Warrant Liability Valuation Assumptions (Detail) - Private Placement Common Stock Warrant Liability | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2021 $ / shares | Dec. 31, 2020 $ / shares
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Stock price (in dollars per share) | $ 68.09 | $ 72.45
Exercise Price |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Exercise price (in dollars per share) | $ 1.12 | $ 1.12
Remaining Term (in years) |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Remaining term (in years) | 2 years 14 days | 2 years 3 months 10 days
Volatility |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative liability measurement input | 0.7200 | 0.7300
Risk Free Interest Rate |  |
Fair Value Measurement Inputs and Valuation Techniques [Line Items] |  |
Derivative liability measurement input | 0.0017 | 0.0014

X
- Definition Derivative liability exercise price. + References No definition available. + Details
Name: | cdna_DerivativeLiabilityExercisePrice
Namespace Prefix: | cdna_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Derivative liability term. + References No definition available. + Details
Name: | cdna_DerivativeLiabilityTerm
Namespace Prefix: | cdna_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of input used to measure derivative liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_DerivativeLiabilityMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

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_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Price of a single share of a number of saleable stocks of a company. + References No definition available. + Details
Name: | us-gaap_SharePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=cdna_PrivatePlacementCommonStockWarrantLiabilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExercisePriceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputExpectedTermMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputPriceVolatilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputRiskFreeInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |