Business Acquisition Cash Consideration

No definition available.

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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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Period Type:	duration

- Definition

Business Acquisitions Pro Forma Adjustment Increase (Decrease) in Income Tax Expense (Benefit)

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Contingent Consideration Milestone Measurement Period One

+ References

No definition available.

+ Details

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- Definition

Number of Commercial Tests

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

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Balance Type:	na
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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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Balance Type:	na
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- Details

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Period Type:	duration

- 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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

+ References

+ 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

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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Balance Type:	credit
Period Type:	instant

- 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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Period Type:	duration

- 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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Data Type:	xbrli:durationItemType
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Period Type:	duration

- 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

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-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

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- Details

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Business Combination - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	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					17,200,000
Business acquisition purchase price, cash					600,000
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	2,500			2,500
Milestone measurement period	6 years
Goodwill acquired in business combination, estimated fair value					12,000,000
Estimated remaining useful life of patent	15 years
Business combination pro forma removal (addition) in income tax benefit	1,500,000	1,500,000
ImmuMetrix, Inc. [Member] \| CareDx, Inc [Member]
Business Acquisition [Line Items]
Acquisition-related costs	1,700,000
Stock-based compensation	200,000
ImmuMetrix, Inc. [Member] \| Contingent consideration [Member]
Business Acquisition [Line Items]
Shares issued, shares issuable upon achievement of future milestone, and options assumed				227,845
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					6,700,000
Accumulated amortization of intangible asset	0			0
ImmuMetrix, Inc. [Member] \| Series G Preferred Stock [Member]
Business Acquisition [Line Items]
Shares issued, shares issuable upon achievement of future milestone, and options assumed					911,364
Estimated fair value					14,200,000
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					227,845
Estimated fair value				1,100,000	2,300,000
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					23,229
Estimated fair value					$ 369,000