Document and Entity Information (USD $)	12 Months Ended
	Jun. 30, 2013	Aug. 01, 2013	Dec. 31, 2012
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY
Trading Symbol	MYGN
Entity Registrant Name	MYRIAD GENETICS INC
Entity Central Index Key	0000899923
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		80,446,692
Entity Public Float			$ 2,209,171,779