Description of Business	6 Months Ended
Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Mirati Therapeutics, Inc. ("Mirati" or the "Company") is a clinical-stage oncology company developing product candidates to address the genetic and immunological promoters of cancer. The Company was incorporated under the laws of the State of Delaware on April 29, 2013 as Mirati Therapeutics, Inc. and is located in San Diego, California. The Company has a wholly owned subsidiary in Canada, MethylGene, Inc., and operates in one business segment, primarily in the United States. The Company's common stock has been listed on the NASDAQ Global Select Market since June 5, 2018, and was previously listed on the NASDAQ Capital Market since July 15, 2013, under the ticker symbol "MRTX."

The entire disclosure for the nature of an entity's business, major products or services, principal markets including location, and the relative importance of its operations in each business and the basis for the determination, including but not limited to, assets, revenues, or earnings. For an entity that has not commenced principal operations, disclosures about the risks and uncertainties related to the activities in which the entity is currently engaged and an understanding of what those activities are being directed toward.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e5967-108592

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-URI http://asc.fasb.org/topic&trid=2134479

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