v2.4.1.9

Business Combination - Additional Information (Detail) (USD $) | 12 Months Ended | 0 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2014 CommercialTests | Jun. 10, 2014
Business Acquisition [Line Items] |  |  |  |  |
Goodwill acquired in business combination, estimated fair value | $ 12,005,000us-gaap_Goodwill | $ 0us-gaap_Goodwill |  | 12,005,000us-gaap_Goodwill |
Stock-based compensation | 535,000us-gaap_ShareBasedCompensation | 72,000us-gaap_ShareBasedCompensation | 69,000us-gaap_ShareBasedCompensation |  |
ImmuMetrix, Inc. [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Acquisition date | Jun. 10, 2014 |  |  |  |
Estimated purchase price |  |  |  |  | 17,200,000us-gaap_BusinessCombinationConsiderationTransferred1 / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember
Business acquisition purchase price, cash |  |  |  |  | 600,000cdna_BusinessAcquisitionCashConsideration / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember
Milestone description | The milestone will be achieved if the Company completes 2,500 commercial tests involving the measurement of cfDNA in organ transplant recipients in the United States no later than six years after the closing date of the acquisition. |  |  |  |
Number of commercial tests involving the measurement of cfDNA to be completed | 2,500cdna_NumberOfCommercialTests / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember |  |  | 2,500cdna_NumberOfCommercialTests / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember |
Milestone measurement period | 6 years |  |  |  |
Goodwill acquired in business combination, estimated fair value |  |  |  |  | 12,000,000us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember
Estimated remaining useful life of patent | 15 years |  |  |  |
Business combination pro forma removal (addition) in income tax benefit | 1,500,000cdna_BusinessAcquisitionsProFormaAdjustmentIncreaseDecreaseInIncomeTaxExpenseBenefit / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember | 1,500,000cdna_BusinessAcquisitionsProFormaAdjustmentIncreaseDecreaseInIncomeTaxExpenseBenefit / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember |  |  |
ImmuMetrix, Inc. [Member] | CareDx, Inc [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Acquisition-related costs | 1,700,000cdna_BusinessAcquisitionCostOfAcquiredEntityTransactionCostsExpensedDuringPeriod / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / dei_LegalEntityAxis = us-gaap_ParentCompanyMember |  |  |  |
Stock-based compensation | 200,000us-gaap_ShareBasedCompensation / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / dei_LegalEntityAxis = us-gaap_ParentCompanyMember |  |  |  |
ImmuMetrix, Inc. [Member] | Contingent consideration [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Shares issued, shares issuable upon achievement of future milestone, and options assumed |  |  |  | 227,845us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_ContingentConsiderationByTypeAxis = cdna_ContingentPaymentMember |
Milestone description | The issuance will occur if the Company completes 2,500 commercial tests involving the measurement of cfDNA in organ transplant recipients in the United States by June 10, 2020. |  |  |  |
ImmuMetrix, Inc. [Member] | In-process technology [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Assets acquired in business combination, estimated fair value |  |  |  |  | 6,700,000us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_InProcessResearchAndDevelopmentMember
Accumulated amortization of intangible asset | 0us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_InProcessResearchAndDevelopmentMember |  |  | 0us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_InProcessResearchAndDevelopmentMember |
ImmuMetrix, Inc. [Member] | Series G Preferred Stock [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Shares issued, shares issuable upon achievement of future milestone, and options assumed |  |  |  |  | 911,364us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember
Estimated fair value |  |  |  |  | 14,200,000us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember
ImmuMetrix, Inc. [Member] | Series G Preferred Stock [Member] | Contingent consideration [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Shares issued, shares issuable upon achievement of future milestone, and options assumed |  |  |  |  | 227,845us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_ContingentConsiderationByTypeAxis = cdna_ContingentPaymentMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember
Estimated fair value |  |  |  | 1,100,000us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_ContingentConsiderationByTypeAxis = cdna_ContingentPaymentMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember | 2,300,000us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_ContingentConsiderationByTypeAxis = cdna_ContingentPaymentMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember
ImmuMetrix, Inc. [Member] | Series G Preferred Stock [Member] | Stock Options [Member] |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Shares issued, shares issuable upon achievement of future milestone, and options assumed |  |  |  |  | 23,229us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_OptionIndexedToIssuersEquityTypeAxis = us-gaap_EmployeeStockOptionMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember
Estimated fair value |  |  |  |  | $ 369,000us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable / us-gaap_BusinessAcquisitionAxis = cdna_ImmumetrixIncMember / us-gaap_OptionIndexedToIssuersEquityTypeAxis = us-gaap_EmployeeStockOptionMember / us-gaap_StatementClassOfStockAxis = us-gaap_SeriesGPreferredStockMember

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- Definition Business Acquisition Cost of Acquired Entity Transaction Costs Expensed During Period + References No definition available. + Details
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- Definition Business Acquisitions Pro Forma Adjustment Increase (Decrease) in Income Tax Expense (Benefit) + References No definition available. + Details
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- Definition Date when the business acquisition agreement was executed, in CCYY-MM-DD format. + References No definition available. + Details
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- Definition Number of shares of equity interests issued or issuable to acquire entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(4) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 + Details
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- Definition For contingent consideration arrangements recognized in connection with a business combination, this element represents a description of such arrangements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, resulting from a business combination. + References No definition available. + Details
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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 + Details
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- Definition The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
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