v2.4.1.9

Stock Incentive Plans - Schedule of Shares Issued and Associated Expense (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares Issued	8,277us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod	4,899us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod	13,176us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod
Fair Market Value per Share at Date of Issuance	$ 7.25us-gaap_SharePrice	$ 7.03us-gaap_SharePrice	$ 7.25us-gaap_SharePrice	$ 8.97us-gaap_SharePrice
Fair Value of Shares Issued	$ 60,008cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodFairValue	$ 34,440cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodFairValue	$ 94,448cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodFairValue

X

- Definition

Share Based Compensation Arrangement By Share Based Payment Award Shares Issued In Period Fair Value

+ References

No definition available.

+ Details

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X

- Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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X

- Definition

Number of share instruments newly issued under a share-based compensation plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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X

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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Period Type:	instant