Description of Business	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
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 the Netherlands, Mirati Therapeutics B.V. (“Mirati B.V.”), and a wholly owned subsidiary in Switzerland, Mirati Therapeutics (Suisse) GmbH (“Mirati Suisse”). The Company's wholly-owned subsidiary in Canada, MethylGene, Inc. (“MethylGene”), was reorganized in August 2022 and is in the process of formally dissolving. As a result of the reorganization, the Company recognized a gain of $9.5 million within other income during the quarter ended September 30, 2022, which represented the cumulative foreign currency translation gain within accumulated other comprehensive income. The Company operates as 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.”