Company and Nature of Business	12 Months Ended
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Company and Nature of Business	Note 1. Company and Nature of Business Personalis, Inc. (the "Company" or "Personalis") develops and markets advanced genomic tests and analytics for precision oncology and personalized testing. The Company also provides sequencing and data analysis services to support population sequencing initiatives. Genomic tests are sold primarily to pharmaceutical companies, biopharmaceutical companies, diagnostics companies, universities, non-profits, and government entities, while services for population sequencing initiatives are sold primarily to government entities. The principal markets for the Company’s services are in the United States and Europe. The Company is expanding its business model to offer genomic tests directly to cancer patients in a clinical setting. However, revenue generated from clinical customers was not significant for any periods presented in these consolidated financial statements. The Company was incorporated in Delaware in February 2011 and began operations in September 2011. The Company formed a wholly owned subsidiary, Personalis (UK) Ltd., in August 2013 and a wholly owned subsidiary, Shanghai Personalis Biotechnology Co., Ltd., which is referred to as “Personalis (Shanghai) Ltd” herein, in October 2020. During the first half of 2023, the Company terminated its operations in China and the Company completed the process of dissolving the Personalis (Shanghai) Ltd entity in February 2024. Refer to Note 9 for further information. The Company operates and manages its business as one reportable operating segment, which is the sale of sequencing and data analysis services. The Company has incurred losses to date and expects to incur additional losses for the foreseeable future. The Company continues to invest the majority of its resources in the development and growth of its business, including investments in product development and studies to prove the clinical validity and utility of the Company's tests. The Company’s activities have been financed to date primarily through the sale of its equity securities and cash from operations.

Company and Nature of Business

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Note 1. Company and Nature of Business

Personalis, Inc. (the "Company" or "Personalis") develops and markets advanced genomic tests and analytics for precision oncology and personalized testing. The Company also provides sequencing and data analysis services to support population sequencing initiatives. Genomic tests are sold primarily to pharmaceutical companies, biopharmaceutical companies, diagnostics companies, universities, non-profits, and government entities, while services for population sequencing initiatives are sold primarily to government entities. The principal markets for the Company’s services are in the United States and Europe.

The Company is expanding its business model to offer genomic tests directly to cancer patients in a clinical setting. However, revenue generated from clinical customers was not significant for any periods presented in these consolidated financial statements.

The Company was incorporated in Delaware in February 2011 and began operations in September 2011. The Company formed a wholly owned subsidiary, Personalis (UK) Ltd., in August 2013 and a wholly owned subsidiary, Shanghai Personalis Biotechnology Co., Ltd., which is referred to as “Personalis (Shanghai) Ltd” herein, in October 2020. During the first half of 2023, the Company terminated its operations in China and the Company completed the process of dissolving the Personalis (Shanghai) Ltd entity in February 2024. Refer to Note 9 for further information. The Company operates and manages its business as one reportable operating segment, which is the sale of sequencing and data analysis services.

The Company has incurred losses to date and expects to incur additional losses for the foreseeable future. The Company continues to invest the majority of its resources in the development and growth of its business, including investments in product development and studies to prove the clinical validity and utility of the Company's tests. The Company’s activities have been financed to date primarily through the sale of its equity securities and cash from operations.