XML 86 R49.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Acquisitions - Summary of Changes to Goodwill Balance (Detail) - USD ($) $ in Millions | 3 Months Ended | 15 Months Ended
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2019
Goodwill [Line Items] |  |
Ending balance |  | $ 408.1
Counsyl Inc [Member] |  |
Goodwill [Line Items] |  |
Beginning balance | $ 94.9 | 94.9
Fair value adjustment to equipment |  | 0.7
Intangible adjustment |  | 2.9
Working capital adjustment | $ (1.1) | (1.1)
Change in deferred tax liability |  | 1.9
Ending balance |  | $ 99.3

X
- Definition Goodwill adjustment to deferred tax assets liabilities. + References No definition available. + Details
Name: | mygn_GoodwillAdjustmentToDeferredTaxAssetsLiabilities
Namespace Prefix: | mygn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Goodwill, intangible adjustments. + References No definition available. + Details
Name: | mygn_GoodwillIntangibleAdjustments
Namespace Prefix: | mygn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_GoodwillLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e961-128460 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillPurchaseAccountingAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of transfers into (out of) an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillTransfers
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=mygn_CounsylIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |