Subsequent Event	12 Months Ended
Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Event	19. SUBSEQUENT EVENT Acquisition of Counsyl, Inc. On July 31, 2018, Company completed the acquisition of Counsyl, Inc. (“Counsyl”), a leading provider of genetic testing and DNA analysis services, pursuant to the Agreement and Plan of Merger (the “Merger Agreement”), dated May 25, 2018. Pursuant to the terms of the Merger Agreement, Myriad Merger Sub, Inc., a newly-created wholly-owned subsidiary of the Company, was merged with and into Counsyl, with Counsyl continuing as the surviving corporation and a wholly-owned subsidiary of Myriad. The Company believes the acquisition allows for greater entry into the high-growth reproductive testing market, with the ability to become a leader in women’s health genetic testing. The transaction will be accounted for as a business combination. The Company acquired Counsyl for preliminary consideration of $407.8, consisting of $280.4 in cash, financed in part by the Amended Facility (see below) and 2,994,251 shares of common stock issued, valued at $127.3. The purchase price is subject to revision through certain working capital adjustments, which are expected to be finalized by the end of the Company’s first quarter of fiscal 2019. Given the timing of the closing of this transaction, we are currently in the process of valuing the assets acquired and liabilities assumed in the business combination. As a result, we are not yet able to provide the amounts to be recognized as of the acquisition date for the major classes of assets acquired and liabilities assumed and other related disclosures. We will disclose this and other related information in our Form 10-Q for the quarter ended September 30, 2018. Amendment to Credit Agreement In connection with the acquisition of Counsyl, the Company entered into Amendment No. 1 (the “Amendment”), by and among Myriad, as borrower, the lenders party thereto and JPMorgan Chase Bank, N.A., as Administrative Agent (the “Agent”), amending the Credit Agreement, dated as of December 23, 2016 (the “Credit Agreement”). The Amendment effects an “amend and extend” transaction with respect to the Company’s existing senior secured revolving credit facility (the “Facility”) by which the maturity date thereof was extended to July 31, 2023 and the maximum aggregate principal commitment was increased from $300.0 to $350.0. Other than the extended maturity date and increase in commitment amount, the agreement did not impact or amend the Facility's previously disclosed terms, including its covenants, events of default, or terms of payment. The proceeds of the Facility were used to (i) finance the acquisition of Counsyl, (ii) pay fees, commissions, transactions costs and expenses incurred in connection with the foregoing, and (iii) for working capital and other general corporate purposes.

19. SUBSEQUENT EVENT

Acquisition of Counsyl, Inc.

On July 31, 2018, Company completed the acquisition of Counsyl, Inc. (“Counsyl”), a leading provider of genetic testing and DNA analysis services, pursuant to the Agreement and Plan of Merger (the “Merger Agreement”), dated May 25, 2018. Pursuant to the terms of the Merger Agreement, Myriad Merger Sub, Inc., a newly-created wholly-owned subsidiary of the Company, was merged with and into Counsyl, with Counsyl continuing as the surviving corporation and a wholly-owned subsidiary of Myriad. The Company believes the acquisition allows for greater entry into the high-growth reproductive testing market, with the ability to become a leader in women’s health genetic testing. The transaction will be accounted for as a business combination.

The Company acquired Counsyl for preliminary consideration of $407.8, consisting of $280.4 in cash, financed in part by the Amended Facility (see below) and 2,994,251 shares of common stock issued, valued at $127.3. The purchase price is subject to revision through certain working capital adjustments, which are expected to be finalized by the end of the Company’s first quarter of fiscal 2019.

Given the timing of the closing of this transaction, we are currently in the process of valuing the assets acquired and liabilities assumed in the business combination. As a result, we are not yet able to provide the amounts to be recognized as of the acquisition date for the major classes of assets acquired and liabilities assumed and other related disclosures. We will disclose this and other related information in our Form 10-Q for the quarter ended September 30, 2018.

Amendment to Credit Agreement

In connection with the acquisition of Counsyl, the Company entered into Amendment No. 1 (the “Amendment”), by and among Myriad, as borrower, the lenders party thereto and JPMorgan Chase Bank, N.A., as Administrative Agent (the “Agent”), amending the Credit Agreement, dated as of December 23, 2016 (the “Credit Agreement”). The Amendment effects an “amend and extend” transaction with respect to the Company’s existing senior secured revolving credit facility (the “Facility”) by which the maturity date thereof was extended to July 31, 2023 and the maximum aggregate principal commitment was increased from $300.0 to $350.0. Other than the extended maturity date and increase in commitment amount, the agreement did not impact or amend the Facility's previously disclosed terms, including its covenants, events of default, or terms of payment.

The proceeds of the Facility were used to (i) finance the acquisition of Counsyl, (ii) pay fees, commissions, transactions costs and expenses incurred in connection with the foregoing, and (iii) for working capital and other general corporate purposes.