Document and Entity Information (USD $)
12 Months Ended
Dec. 31, 2014
Feb. 27, 2015
Document And Entity Information [Abstract]    
Document Type 10-K  
Amendment Flag false  
Document Period End Date Dec. 31, 2014  
Document Fiscal Year Focus 2014  
Document Fiscal Period Focus FY  
Trading Symbol CDNA  
Entity Registrant Name CareDx, Inc.  
Entity Central Index Key 0001217234  
Current Fiscal Year End Date --12-31  
Entity Well-known Seasoned Issuer No  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   11,814,825
Entity Public Float $ 49,411,679