Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 29, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q2
Trading Symbol	CDNA
Entity Registrant Name	CareDx, Inc.
Entity Central Index Key	0001217234
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		18,976,343