Description of Business	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of BusinessMirati 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. (“MethylGene”), a wholly owned subsidiary in the Netherlands (“Mirati Therapeutics B.V.”) 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, in each case under the ticker symbol “MRTX.”