Organization and Description of Business	12 Months Ended
Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business Mirum Pharmaceuticals, Inc. (the “Company”) was incorporated in the State of Delaware on May 2, 2018, and is headquartered in Foster City, California. The Company is a biopharmaceutical company focused on the identification, acquisition, development and commercialization of novel therapies for debilitating rare and orphan diseases. The Company has three approved medicines: LIVMARLI® (maralixibat) oral solution (“Livmarli”), Cholbam® (cholic acid) capsules, and Chenodal® (chenodiol) tablets (“Chenodal”). Livmarli is approved for the treatment of cholestatic pruritus in patients with Alagille syndrome (“ALGS”) three months of age and older and cholestatic pruritus in patients with primary familial intrahepatic cholestasis (“PFIC”) five years of age and older in the United States, and for the treatment of cholestatic pruritus in patients with ALGS two months of age and older in Europe. On July 16, 2023, the Company entered into an Asset Purchase Agreement (the “Purchase Agreement”) with Travere Therapeutics, Inc., a Delaware corporation (“Travere”), pursuant to which, upon the closing in August 2023, the Company acquired Travere’s bile acid product portfolio, including Chenodal and Cholbam (also known as Kolbam, and together with Chenodal, the “Bile Acid Medicines”), two therapies addressing rare diseases in high-need settings (such acquisition, the “Bile Acid Portfolio Acquisition”) (Note 7). Cholbam is FDA-approved for the treatment of bile acid synthesis disorders due to single enzyme deficiencies and adjunctive treatment of peroxisomal disorders in patients who show signs or symptoms or liver disease. Chenodal is approved for the treatment of radiolucent stones in the gallbladder and has received medical necessity recognition by the FDA for the treatment of cerebrotendinous xanthomatosis (“CTX”). The Company’s development pipeline consists of the clinical-stage product candidate volixibat and life-cycle extension opportunities for Livmarli. The Company commenced significant operations in November 2018. The Company views its operations and manages its business as one operating segment. The Company determined its operating segment on the same basis that it uses to evaluate its performance internally. Liquidity The Company has a limited operating history, has incurred significant operating losses since its inception, and the revenue and income potential of the Company’s business and market are unproven. As of December 31, 2023, the Company had an accumulated deficit of $556.2 million and cash and cash equivalents of $286.3 million. The Company believes that its cash and cash equivalents of $286.3 million as of December 31, 2023 provide sufficient capital resources to continue its operations for at least twelve months from the issuance date of the accompanying consolidated financial statements. The consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty. Management expects to continue to incur additional substantial losses in the foreseeable future as a result of the Company’s research and development activities. In April 2023, the Company completed a convertible notes offering, as further described in Note 10, with net proceeds of $305.3 million, after deducting the initial purchasers’ discounts and commissions and offering expenses. From the net proceeds, $192.7 million was used to repurchase all future revenue interests (the “Revenue Interests”) in connection with the Company’s Revenue Interest Purchase Agreement (“RIPA”) (Note 6). Upon repurchase and the termination of the RIPA, in accordance with its terms, the previously restricted cash equivalents of $100.0 million were no longer restricted from use. In August 2023, the Company completed the Bile Acid Portfolio Acquisition contemplated by the Purchase Agreement and acquired substantially all of the assets of Travere that are primarily related to the development, manufacture and commercialization of the Bile Acid Medicines. Under the terms of the Purchase Agreement, the Company paid an upfront purchase price of $210.4 million in cash to Travere and may pay additional amounts of up to $235.0 million upon the achievement of certain milestones based on specified amounts of net annual sales of the Bile Acid Medicines. In connection with and immediately prior to the closing of the Bile Acid Portfolio Acquisition, the Company completed the private placement of 8,000,000 shares of the Company's common stock at a price per share of $26.25, resulting in net proceeds of approximately $202.2 million.

Organization and Description of Business

12 Months Ended

Dec. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization and Description of Business

1. Organization and Description of Business

Mirum Pharmaceuticals, Inc. (the “Company”) was incorporated in the State of Delaware on May 2, 2018, and is headquartered in Foster City, California. The Company is a biopharmaceutical company focused on the identification, acquisition, development and commercialization of novel therapies for debilitating rare and orphan diseases.

The Company has three approved medicines: LIVMARLI® (maralixibat) oral solution (“Livmarli”), Cholbam® (cholic acid) capsules, and Chenodal® (chenodiol) tablets (“Chenodal”). Livmarli is approved for the treatment of cholestatic pruritus in patients with Alagille syndrome (“ALGS”) three months of age and older and cholestatic pruritus in patients with primary familial intrahepatic cholestasis (“PFIC”) five years of age and older in the United States, and for the treatment of cholestatic pruritus in patients with ALGS two months of age and older in Europe.

On July 16, 2023, the Company entered into an Asset Purchase Agreement (the “Purchase Agreement”) with Travere Therapeutics, Inc., a Delaware corporation (“Travere”), pursuant to which, upon the closing in August 2023, the Company acquired Travere’s bile acid product portfolio, including Chenodal and Cholbam (also known as Kolbam, and together with Chenodal, the “Bile Acid Medicines”), two therapies addressing rare diseases in high-need settings (such acquisition, the “Bile Acid Portfolio Acquisition”) (Note 7). Cholbam is FDA-approved for the treatment of bile acid synthesis disorders due to single enzyme deficiencies and adjunctive treatment of peroxisomal disorders in patients who show signs or symptoms or liver disease. Chenodal is approved for the treatment of radiolucent stones in the gallbladder and has received medical necessity recognition by the FDA for the treatment of cerebrotendinous xanthomatosis (“CTX”).

The Company’s development pipeline consists of the clinical-stage product candidate volixibat and life-cycle extension opportunities for Livmarli. The Company commenced significant operations in November 2018.

The Company views its operations and manages its business as one operating segment. The Company determined its operating segment on the same basis that it uses to evaluate its performance internally.

Liquidity

The Company has a limited operating history, has incurred significant operating losses since its inception, and the revenue and income potential of the Company’s business and market are unproven. As of December 31, 2023, the Company had an accumulated deficit of $556.2 million and cash and cash equivalents of $286.3 million. The Company believes that its cash and cash equivalents of $286.3 million as of December 31, 2023 provide sufficient capital resources to continue its operations for at least twelve months from the issuance date of the accompanying consolidated financial statements. The consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty. Management expects to continue to incur additional substantial losses in the foreseeable future as a result of the Company’s research and development activities.

In April 2023, the Company completed a convertible notes offering, as further described in Note 10, with net proceeds of $305.3 million, after deducting the initial purchasers’ discounts and commissions and offering expenses. From the net proceeds, $192.7 million was used to repurchase all future revenue interests (the “Revenue Interests”) in connection with the Company’s Revenue Interest Purchase Agreement (“RIPA”) (Note 6). Upon repurchase and the termination of the RIPA, in accordance with its terms, the previously restricted cash equivalents of $100.0 million were no longer restricted from use.

In August 2023, the Company completed the Bile Acid Portfolio Acquisition contemplated by the Purchase Agreement and acquired substantially all of the assets of Travere that are primarily related to the development, manufacture and commercialization of the Bile Acid Medicines. Under the terms of the Purchase Agreement, the

Company paid an upfront purchase price of $210.4 million in cash to Travere and may pay additional amounts of up to $235.0 million upon the achievement of certain milestones based on specified amounts of net annual sales of the Bile Acid Medicines. In connection with and immediately prior to the closing of the Bile Acid Portfolio Acquisition, the Company completed the private placement of 8,000,000 shares of the Company's common stock at a price per share of $26.25, resulting in net proceeds of approximately $202.2 million.