Contingent Value Right

No definition available.

Name:	mrtx_ContingentValueRight
Namespace Prefix:	mrtx_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Sale of Stock, Aggregate Offering Price

+ References

No definition available.

+ Details

Name:	mrtx_SaleofStockAggregateOfferingPrice
Namespace Prefix:	mrtx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483399/855-10-50-2

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=mrtx_BMSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
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Subsequent Event - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 08, 2023	Sep. 30, 2023	Dec. 31, 2022	Jul. 02, 2021
Subsequent Event [Line Items]
Common stock, par value (USD per share)		$ 0.001	$ 0.001
Amended and Restated At the Market Facility
Subsequent Event [Line Items]
Common stock, par value (USD per share)				$ 0.001
Aggregate offering price				$ 500.0
Subsequent Event
Subsequent Event [Line Items]
Common stock, par value (USD per share)	$ 0.001
Contingent Value Right (in USD per share)	12.00
Subsequent Event \| Merger Agreement
Subsequent Event [Line Items]
Business Acquisition, Share Price (in USD per share)	$ 58.00
Subsequent Event \| BMS
Subsequent Event [Line Items]
Gain (Loss) on Contract Termination	$ 168.0
Subsequent Event \| Mirati
Subsequent Event [Line Items]
Gain (Loss) on Contract Termination	$ 240.0