Mirum Pharmaceuticals (MIRM) 10-Q 8 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	May 03, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-38981
Entity Registrant Name	Mirum Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-1281555
Entity Address, Address Line One	950 Tower Lane, Suite 1050,
Entity Address, City or Town	Foster City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94404
City Area Code	650
Local Phone Number	667-4085
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	MIRM
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		47,133,021
Entity Central Index Key	0001759425
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 302,843	$ 286,326
Accounts receivable	54,999	67,968
Inventory	21,606	22,312
Prepaid expenses and other current assets	10,017	10,935
Total current assets	389,465	387,541
Property and equipment, net	501	706
Operating lease right-of-use assets	680	1,284
Intangible assets, net	257,443	252,925
Other assets	3,873	4,165
Total assets	651,962	646,621
Current liabilities:
Accounts payable	15,983	7,416
Accrued expenses	89,568	78,544
Operating lease liabilities	358	1,104
Total current liabilities	105,909	87,064
Operating lease liabilities, noncurrent	328	617
Convertible notes payable, net	306,835	306,421
Other liabilities	4,287	3,849
Total liabilities	417,359	397,951
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized, and no shares issued and outstanding as of March 31, 2024 and December 31, 2023	0	0
Common stock, $0.0001 par value; 200,000,000 shares authorized; 47,061,106 and 46,723,143 shares issued and outstanding as of March 31, 2024 and December 31, 2023, respectively	5	5
Additional paid-in capital	816,129	803,260
Accumulated deficit	(581,518)	(556,239)
Accumulated other comprehensive (loss) income	(13)	1,644
Total stockholders’ equity	234,603	248,670
Total liabilities and stockholders’ equity	$ 651,962	$ 646,621

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	47,061,106	46,723,143
Common stock, shares outstanding (in shares)	47,061,106	46,723,143

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue:
Total revenue	$ 69,222	$ 31,598
Operating expenses:
Cost of sales	17,830	4,979
Research and development	32,222	23,548
Selling, general and administrative	45,638	30,219
Total operating expenses	95,690	58,746
Loss from operations	(26,468)	(27,148)
Other income (expense):
Interest income	3,633	2,272
Interest expense	(3,577)	(4,242)
Other income (expense), net	1,757	(811)
Net loss before provision for income taxes	(24,655)	(29,929)
Provision for income taxes	624	201
Net loss	$ (25,279)	$ (30,130)
Net loss per share, basic (in dollars per share)	$ (0.54)	$ (0.80)
Net loss per share, diluted (in dollars per share)	$ (0.54)	$ (0.80)
Weighted-average shares of common stock outstanding, basic (in shares)	46,927,550	37,675,306
Weighted-average shares of common stock outstanding, diluted (in shares)	46,927,550	37,675,306
Product sales, net
Revenue:
Total revenue	$ 68,917	$ 29,098
License and other revenue
Revenue:
Total revenue	$ 305	$ 2,500

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (25,279)	$ (30,130)
Other comprehensive income (loss):
Unrealized gain on available-for-sale investments	0	165
Cumulative translation adjustments	(1,657)	188
Comprehensive loss	$ (26,936)	$ (29,777)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Equity Award Plan	At The Market Offering	Common Stock	Common Stock Equity Award Plan	Common Stock At The Market Offering	Additional Paid-In Capital	Additional Paid-In Capital Equity Award Plan	Additional Paid-In Capital At The Market Offering	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2022				36,956,345
Beginning balance at Dec. 31, 2022	$ 142,037			$ 4			$ 535,074			$ (392,824)	$ (217)
Issuance of common stock in connection with equity award plans (in shares)					197,703
Issuance of common stock in connection with equity award plans		$ 1,390						$ 1,390
Issuance of common stock in at-the-market offerings, net of issuance costs (in shares)						658,206
Issuance of common stock in at-the-market offerings, net of issuance costs			$ 14,480						$ 14,480
Issuance of common stock in connection with achievement of Contingent Milestone (in shares)				199,993
Issuance of common stock in connection with achievement of Contingent Milestone	4,292						4,292
Stock-based compensation	8,728						8,728
Net loss	(30,130)									(30,130)
Other comprehensive (loss) income	353										353
Ending balance (in shares) at Mar. 31, 2023				38,012,247
Ending balance at Mar. 31, 2023	141,150			$ 4			563,964			(422,954)	136
Beginning balance (in shares) at Dec. 31, 2023				46,723,143
Beginning balance at Dec. 31, 2023	248,670			$ 5			803,260			(556,239)	1,644
Issuance of common stock in connection with equity award plans (in shares)					337,963
Issuance of common stock in connection with equity award plans		$ 1,205						$ 1,205
Issuance of common stock in connection with achievement of Contingent Milestone	0
Stock-based compensation	11,664						11,664
Net loss	(25,279)									(25,279)
Other comprehensive (loss) income	(1,657)										(1,657)
Ending balance (in shares) at Mar. 31, 2024				47,061,106
Ending balance at Mar. 31, 2024	$ 234,603			$ 5			$ 816,129			$ (581,518)	$ (13)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
At The Market Offering
Issuance costs	$ 518

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities
Net loss	$ (25,279)	$ (30,130)
Reconciliation of net loss to net cash provided by (used in) operating activities:
Stock-based compensation	11,450	8,561
Depreciation and amortization	5,664	1,337
Inventory reserves and firm commitment losses	237	0
Costs recognized on sale of acquired inventory	2,209	0
Amortization of debt discount and offering costs	414	0
Non-cash interest expense related to the revenue interest liability	0	4,242
Unrealized foreign exchange gain	(1,734)	0
Other	518	(153)
Change in operating assets and liabilities:
Accounts receivable	12,969	(667)
Prepaid and other current assets	918	(40)
Inventory	(3,173)	(778)
Other assets	11	285
Accounts payable, accrued expenses and other liabilities	11,277	(1,212)
Operating lease liabilities	(269)	(219)
Net cash provided by (used in) operating activities	15,212	(18,774)
Investing activities
Purchase of investments	0	(22,444)
Proceeds from maturities of investments	0	64,500
Purchase of property and equipment	(13)	(41)
Payments made for additions to intangible assets	0	(15,000)
Net cash (used in) provided by investing activities	(13)	27,015
Financing activities
Proceeds from issuance of common stock in at-the-market offerings, net of issuance costs	0	14,480
Proceeds from issuance of common stock pursuant to equity plans	1,205	1,390
Payments on revenue interest liability	0	(2,883)
Net cash provided by financing activities	1,205	12,987
Effect of exchange rate on cash, cash equivalents and restricted cash equivalents	113	188
Net increase in cash, cash equivalents and restricted cash equivalents	16,517	21,416
Cash, cash equivalents and restricted cash equivalents at beginning of period	286,326	128,003
Cash, cash equivalents and restricted cash equivalents at end of period	302,843	149,419
Supplemental disclosure of cash flow information:
Operating cash flows paid for operating lease	289	262
Cash paid for income taxes	139	0
Non-cash operating, investing and financing activities:
Accrued milestone payments classified as intangible assets, net	10,000	0
Increase (decrease) of inventory purchases included in accounts payable and accrued liabilities	(1,731)	103
Decrease in ROU assets and lease liabilities due to lease modification	723	0
Stock-based compensation capitalized to inventory	214	167
Issuance of common stock in connection with settlement of Contingent Milestone liability	0	4,292
Deferred offering costs in accrued liabilities	$ 0	$ 240

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	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 dedicated to transforming the treatment of rare diseases affecting children and adults. The Company has three approved medicines: LIVMARLI® (maralixibat) oral solution (“Livmarli”), Cholbam® (cholic acid) capsules (“Cholbam”), 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 August 31, 2023, the Company completed the acquisition of assets of Travere Therapeutics, Inc. (“Travere”) that are primarily related to the development, manufacture (including synthesis, formulation, finishing or packaging) and commercialization of 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 March 31, 2024, the Company had an accumulated deficit of $581.5 million and cash and cash equivalents of $302.8 million. The Company believes that its cash and cash equivalents of $302.8 million as of March 31, 2024, provide sufficient capital resources to continue its operations for at least twelve months from the issuance date of the accompanying unaudited condensed consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, the accompanying unaudited condensed consolidated financial statements do not include all of the information and notes required by GAAP for complete financial statements. The unaudited interim financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The unaudited condensed consolidated balance sheet as of December 31, 2023 has been derived from the audited consolidated financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. The operating results presented in these unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto in the Company’s Annual Report on Form 10-K (“Annual Report”) for the fiscal year ended December 31, 2023, as filed with the SEC on March 15, 2024. Statement of Cash Flows Reclassification Subsequent to the initial filing of the Company’s Quarterly Report on Form 10-Q for the three-month period ended March 31, 2023, the Company identified an immaterial error in the unaudited condensed consolidated statement of cash flows related to the classification of a $15.0 million milestone payment made to Shire International GmBH relating to our Assignment and License Agreement with them. This payment was presented as part of net cash used in operating activities but should have been classified within cash provided by investing activities. The misclassification did not impact the unaudited condensed consolidated balance sheet as of March 31, 2023, nor did it impact the unaudited condensed consolidated statements of operations, comprehensive loss and stockholders’ equity for the three months ended March 31, 2023. The Company concluded this misclassification was not material to the prior period considering both quantitative and qualitative factors as determined by authoritative guidance. The Company has revised the presentation and appropriately classified the payment within investing activities in the unaudited condensed consolidated statement of cash flows for the three-month period ended March 31, 2023, presented within this Quarterly Report on Form 10-Q. Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. These estimates and assumptions are based upon historical experience, knowledge of current events and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results could differ materially from those estimates. The Company’s unaudited condensed consolidated financial statements as of and for the three months ended March 31, 2024 reflect the Company’s estimates of the impact of the geopolitical and macroeconomic environment, including the impact of inflation, bank failures, high interest rates and foreign exchange rate fluctuations. The duration and the scope of these conditions cannot be predicted; therefore, the extent to which these conditions will directly or indirectly impact the Company’s business, results of operations and financial condition, is uncertain. The Company is not aware of any specific event or circumstance that would require an update to its estimates, judgments and assumptions or a revision of the carrying value of the Company’s assets or liabilities as of the date of this filing. Significant Accounting Policies There have been no significant changes to the accounting policies during the three months ended March 31, 2024, as compared to the significant accounting policies described in Note 2 of the “Notes to Consolidated Financial Statements” in the Company’s audited consolidated financial statements included in the Annual Report, unless indicated below. Cash, Cash Equivalents and Restricted Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash without penalty and with original maturities of three months or less at the date of purchase to be cash equivalents. The carrying amounts reported in the unaudited condensed consolidated balance sheets for cash and cash equivalents are valued at cost, which approximate their fair value. Restricted cash equivalents as of March 31, 2023 consisted of deposits placed in a segregated bank account as required under the terms of the Company’s Revenue Interest Purchase Agreement (“RIPA”), as amended September 2021 and March 2022, with Mulholland SA LLC, an affiliate of Oberland Capital LLC, as agent for the purchasers party thereto (the “Purchasers”), and the Purchasers in connection with the sale of the Priority Review Voucher in December 2022. Upon repurchase and the termination of the RIPA in April 2023, in accordance with its terms, the previously restricted cash equivalents of $100.0 million were no longer restricted from use. The following table provides a reconciliation of cash, cash equivalents and restricted cash equivalents reported within the unaudited condensed consolidated balance sheets that together reflect the same amounts shown in the unaudited condensed consolidated statements of cash flows (in thousands): As of March 31, 2024 2023 Cash and cash equivalents $ 302,843 $ 49,419 Restricted cash equivalents — 100,000 Total cash, cash equivalents, and restricted cash equivalents $ 302,843 $ 149,419 Investments The Company classifies all investments in securities as available-for-sale. Management determines the appropriate classification of its investments in securities at the time of purchase. Investments with original maturities beyond three months at the date of purchase and which mature at, or less than twelve months from the balance sheet date, are classified as a current asset. Investments are recorded at fair value, with unrealized gains and losses reported as accumulated other comprehensive income (loss) until realized, with the exception of any declines in fair value below the cost basis that are a result of a credit loss, which, if any, are reported in other income (expense), net in the current period through an allowance for credit losses. Each reporting period, the Company evaluates whether declines in fair values of its available-for-sale securities below their cost basis are a result of credit loss or other factors and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, the creditworthiness of the security issuers, as well as the Company’s ability and intent to hold the available-for-sale security until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any available-for-sale securities before recovery of its amortized cost basis. The cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion, as well as interest and dividends, are included in interest income. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis and are also included in Other income (expense). To date, the Company has not identified any declines in fair value of its investments related to credit loss. Concentrations of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, accounts receivable and investments. The Company limits the amount of credit exposure by investing cash that is not required for immediate operating needs in money market funds, government obligations and/or commercial paper with short maturities. Additionally, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. To date, the Company has not experienced any losses associated with this credit risk and continues to believe that this exposure is not significant. The Company relies on a single distributor and a specialty pharmacy for all of the Company’s sales of its approved medicines in the United States as well as a single distributor for sales of Livmarli outside the United States. The Company sources materials and services through several vendors. Certain materials are sourced from a single vendor. The loss of certain vendors could result in a temporary disruption of the Company’s commercialization efforts. As of March 31, 2024 and as of December 31, 2023, the Company did not have any customers that individually accounted for more than 10% of accounts receivable. For the three months ended March 31, 2024 and 2023, the Company did not have revenue attributable to any one customer in excess of 10% of sales. Accounts Receivable The Company has accounts receivable amounts due from product sales. The Company also has accounts receivable amounts due from license agreements for milestones achieved, but not yet paid. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company estimates the allowance for credit losses using the current expected credit loss model. Under this model, the allowance for credit losses reflects the Company’s estimate of lifetime expected credit losses. The Company evaluates the collectability of the cash flows based on the risk of loss over the contractual life, even when that risk is remote, based on judgments about the creditworthiness of its customers, historical experience and other relevant information that is available to the Company. There was no allowance for credit losses as of March 31, 2024. There was no bad debt expense for the three months ended March 31, 2024 and 2023. Inventory Inventory is valued at the lower of cost or net realizable value, with cost determined on a first-in, first-out (FIFO) basis. The Company periodically reviews the composition of inventory to identify excess, obsolete, slow-moving or otherwise unsaleable items. If unsaleable items are observed and there are no alternate uses for the inventory, the Company will record a write-down to net realizable value in the period that the decline in value is recognized through a charge to cost of sales. Furthermore, the Company periodically reviews its firm commitments for the purchase of minimum order quantities. If the minimum order quantities exceed the Company’s future demand, a net loss is accrued in cost of sales for such future inventory purchases. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required. Accruals for firm purchase commitments amounted to $5.3 million and $5.2 million as of March 31, 2024 and December 31, 2023, respectively, of which $3.9 million and $3.8 million was included in other liabilities on the unaudited condensed consolidated balance sheets as of March 31, 2024 and December 31, 2023, respectively. Intangible Assets, Net The Company accounts for asset acquisitions that do not meet the definition of a business using the cost accumulation method, whereby the cost of the acquisition, including certain transaction costs, is allocated to the asset (or assets) acquired on the basis of its (or their) relative fair value(s) on the measurement date. No goodwill is recognized in an asset acquisition. Intangible assets are measured at their fair values as of the acquisition date or, in the case of commercial milestone payments, the date they become due. The evaluation of intangible assets includes assessing the amortization period for which the asset is expected to contribute to the future cash flows of the Company. Intangible assets with finite useful lives are amortized over their estimated useful lives, primarily on a straight-line basis when the Company is unable to reliably estimate the pattern of cash flow. The Company tests its finite lived intangible assets for impairment annually or if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. If it is determined that the asset is impaired, the carrying value is written down to its estimated fair value, with the related impairment charge recognized in the unaudited condensed consolidated statements of operations in the period in which the impairment occurs. The Company has not recorded any impairments to its intangible assets for any of the periods presented. The components of the Company’s intangible assets were as follows (in thousands, except for weighted-average remaining amortization period): March 31, 2024 Gross Carrying Value Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Amortization Period (Years) Commercial milestones $ 49,000 $ (3,968) $ 45,032 14.3 Developed technology 226,620 (14,991) 211,629 11.4 Assembled workforce 970 (188) 782 2.4 Total intangible assets $ 276,590 $ (19,147) $ 257,443 11.9 December 31, 2023 Gross Carrying Value Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Amortization Period (Years) Commercial milestones $ 39,000 $ (3,318) $ 35,682 16.2 Developed technology 226,620 (10,239) 216,381 11.7 Assembled workforce 970 (108) 862 2.7 Total intangible assets $ 266,590 $ (13,665) $ 252,925 12.3 Amortization expense was $5.5 million and $1.3 million for the three months ended March 31, 2024 and 2023, respectively. Amortization expense was included in cost of sales in the accompanying unaudited condensed consolidated statements of operations. The following table summarizes the estimated future amortization expense associated with the Company’s intangible assets as of March 31, 2024 (in thousands): Amount 2024 (remaining nine months) 17,023 2025 22,698 2026 22,590 2027 22,375 2028 22,375 Thereafter 150,382 $ 257,443 Product Sales, Net The Company recognizes product sales, net when the customer obtains control of our product, which occurs at a point in time, typically upon delivery of the Company’s product to the customer. Revenues from product sales are recorded at the net sales price, or the transaction price, which may include fixed or variable consideration for discounts, government rebates, co-pay assistance, returns and other allowances that are offered within contracts with a customer relating to the sale of the Company's approved medicines. Estimates of variable consideration are calculated based on the actual product sales each reporting period and the nature of the variable consideration related to those sales. Overall, these estimates reflect the Company’s best estimate of the amount of consideration to which the Company expects to be entitled based on the terms of the contract. The amount of variable consideration that is included in the transaction price may be constrained and is included in product sales, net only to the extent that it is considered probable that a significant reversal in the amount of the cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Estimates are reviewed and updated quarterly as additional information becomes known. Actual amounts of consideration ultimately received may differ materially from estimates. If actual results in the future vary from estimates, the Company will adjust these estimates, which would affect product sales, net and earnings in the period such variances are adjusted. Significant categories of sales discounts and allowances are as follows: Government Rebates : The Company records rebates payable under Medicaid and other government programs as a reduction of revenue at the time product revenues are generated. The Company’s rebate calculations may require estimates, including estimates of customer mix, to determine which sales will be subject to rebates and the amount of such rebates. The Company updates its estimates and assumptions on a quarterly basis and records any necessary adjustments to revenue in the period identified. The liability for unpaid rebates is included in accrued expenses on the accompanying unaudited condensed consolidated balance sheets. To date, actual government rebates have not differed materially from the Company’s estimates. Other Incentives : Other incentives include a branded co-pay assistance program for eligible patients with commercial insurance in the United States. The branded co-pay assistance program assists commercially insured patients who have coverage for the Company's approved medicines and is intended to reduce each participating patient’s portion of the financial responsibility of the purchase price up to a specified dollar amount of assistance. The calculation of the accrual for co-pay assistance is based upon an identification of claims and the cost per claims associated with product that has been recognized as revenue. The Company records amounts paid under the brand specific co-pay assistance program for each patient as a reduction of revenue from product sales. To date, actual other incentives have not differed materially from the Company’s estimates. Product Returns : The Company records revenue for product sales, net of estimated product returns. Customers have limited return rights related only to the product’s damage or defect identified upon delivery of the product. The Company estimates the amount of product sales that may be returned and records the estimate as a reduction of revenue and a refund liability in the period the related product revenue is recognized. To date, actual returns have not differed materially from the Company’s estimates. The following table represents Total revenues and disaggregates Product sales, net by approved medicine (in thousands): Three Months Ended March 31, 2024 2023 Product sales, net: Livmarli $ 42,845 $ 29,098 Bile Acid Medicines 26,072 — Total product sales, net 68,917 29,098 License and other revenue 305 2,500 Total revenues $ 69,222 $ 31,598 The following table sets forth Product sales, net by geographic area based on the ship-to location (in thousands): Three Months Ended March 31, 2024 2023 United States $ 56,111 $ 24,614 Rest of the world 12,806 4,484 Total product sales, net $ 68,917 $ 29,098 Foreign Currency The unaudited condensed consolidated financial statements are presented in U.S. dollars. The functional currency for most of the Company’s foreign subsidiaries is their local currency. Balance sheet accounts of international subsidiaries are translated at the current exchange rates as of the end of each accounting period. Income statement items are translated at average exchange rates for the period. The resulting translation adjustments are recorded as a separate component of stockholders’ equity. Foreign currency transaction gains and losses are included in other income (expense), net in the unaudited condensed consolidated statements of operations. Transaction gains and losses result primarily from fluctuations in exchange rates when intercompany receivables and payables are denominated in currencies other than the functional currency of our subsidiary that recorded the transaction. Unrealized foreign exchange gains amounted to $1.7 million for the three months ended March 31, 2024 and were insignificant for the three months ended March 31, 2023. Realized foreign exchange gains and losses were insignificant for the three months ended March 31, 2024 and 2023, respectively. Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average shares of common stock outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. Diluted net loss per share excludes the potential impact of the Company’s common stock subject to repurchase, common stock options, restricted stock units, contingently issuable employee stock purchase plan shares and common stock issuable upon conversion of convertible notes because their effect would be anti-dilutive due to the Company’s net loss. Basic and diluted net loss per share were the same for the three months ended March 31, 2024 and 2023. The following outstanding potential dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect: As of March 31, As of March 31, 2024 2023 Options to purchase common stock and restricted stock units 12,525,389 10,573,024 Common stock issuable upon conversion of convertible notes 9,964,247 — Employee stock purchase plan contingently issuable 48,297 66,658 Shares issuable as contingent consideration in connection with asset acquisition — 31,638 Total 22,537,933 10,671,320 Recent Accounting Pronouncements Not Yet Adopted From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the accompanying unaudited condensed consolidated financial statements and disclosures. In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures (“ASU 2023-07”). This new guidance is designed to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024 on a retrospective basis. Early adoption is permitted. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures (“ASU 2023-09”). This new guidance is designed to enhance the transparency and decision usefulness of income tax disclosures. The amendments of this update are related to the rate reconciliation and income taxes paid. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements by major security type are presented in the following table (in thousands): March 31, 2024 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 281,865 $ — $ — 281,865 Total financial assets $ 281,865 $ — $ — $ 281,865 December 31, 2023 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 278,116 $ — $ — $ 278,116 Total financial assets $ 278,116 $ — $ — $ 278,116 The carrying amounts of certain financial instruments such as cash and cash equivalents, accounts receivable, prepaid expenses, other current assets, accounts payable and accrued expenses as of March 31, 2024 and December 31, 2023 approximate their related fair values due to the short-term maturities of these instruments.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Financial Instruments	Financial Instruments The fair value and amortized cost of cash equivalents and available-for-sale investments by major security type are presented in the following table (in thousands): March 31, 2024 Amortized Unrealized Unrealized Estimated Cash equivalents: Money market funds $ 281,865 $ — $ — $ 281,865 Total cash equivalents $ 281,865 $ — $ — $ 281,865 Classified as: Cash equivalents $ 281,865 Total cash equivalents $ 281,865 December 31, 2023 Amortized Unrealized Unrealized Estimated Cash equivalents: Money market funds $ 278,116 $ — $ — $ 278,116 Total cash equivalents $ 278,116 $ — $ — $ 278,116 Classified as: Cash equivalents $ 278,116 Total cash equivalents $ 278,116 During the three months ended March 31, 2023, there have been no significant realized gains or losses on available-for-sale investments, no investments have been in a continuous unrealized loss position for more than 12 months, and the Company did not recognize any material unrealized gains or losses on these securities. The Company did not hold investments during the three months ended March 31, 2024.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2024
Balance Sheet Components [Abstract]
Balance Sheet Components	Balance Sheet Components Inventory Inventory consists of the following (in thousands): March 31, December 31, Raw materials $ 2,886 $ 2,998 Work in progress 10,850 9,873 Finished goods 7,870 9,441 Total inventory $ 21,606 $ 22,312 Accrued Expenses Accrued expenses consist of the following (in thousands): March 31, December 31, Accrued compensation and related benefits $ 12,040 $ 20,939 Accrued sales deductions 30,005 23,650 Accrued clinical trials 7,678 7,268 Accrued professional service fees 9,318 7,941 Accrued contract manufacturing and non-clinical costs 8,599 9,922 Accrued royalties payable 6,657 6,716 Accrued interest 5,271 2,108 Accrued milestone payment 10,000 — Total accrued expenses $ 89,568 $ 78,544

Revenue Interest Purchase Agree

Revenue Interest Purchase Agreement	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue Interest Purchase Agreement	Revenue Interest Purchase Agreement Except as described below, the Company's Revenue Interest Purchase Agreement with the Purchasers is described in Note 6 of the “Notes to Consolidated Financial Statements” in the Annual Report. The Purchasers had the right to receive certain revenue interests (the “Revenue Interests”) from the Company based on annual product sales, net of Livmarli, in tiered payments (the “Revenue Interest Payments”). Revenue Interest Payments made as a result of the Company’s product sales, net reduce the revenue interest liability. During the three months ended March 31, 2023, the Company made payments of $2.9 million in connection with the RIPA. The Company imputed interest expense associated with this liability using the effective interest rate method. The effective interest rate was calculated based on the rate that would enable the debt to be repaid in full over the anticipated life of the arrangement. The interest rate on this liability varied during the term of the agreement depending on a number of factors, including the level of forecasted product sales, net. The Company evaluated the interest rate quarterly based on its current product sales, net forecasts utilizing the prospective method. The Company recorded interest expense related to this arrangement of $4.2 million for the three months ended March 31, 2023. In April 2023, the Company exercised the its call option in accordance with the RIPA and repurchased all future Revenue Interests. In connection with such repurchase, the Company made a payment of $192.7 million and the RIPA terminated in accordance with its terms.

Asset Acquisitions

Asset Acquisitions	3 Months Ended
	Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
Asset Acquisitions	Asset Acquisitions Asset Purchase Agreement with Travere Therapeutics, Inc. On August 31, 2023, the Company completed the Bile Acid Portfolio Acquisition. In accordance with the terms and conditions of the Asset Purchase Agreement entered into with Travere, the Company purchased from Travere substantially all of the assets related to its business of development, manufacturing (including synthesis, formulation, finishing or packaging) and commercialization of the Bile Acid Medicines. The Company paid $210.4 million upon closing of the transaction, and up to an additional $235.0 million is payable upon the achievement of certain milestones based on specified amounts of annual net sales of the Bile Acid Medicines. The Company accounted for the transaction as an asset acquisition as substantially all the fair value of the gross assets acquired was concentrated in a group of similar identifiable assets, namely, the developed technology related to the Bile Acid Medicines. The developed technology asset consists of certain processes and at-market contracts related to the manufacture and commercialization of the Bile Acid Medicines, regulatory approvals, and other assets, and are considered a single asset as they are interdependently linked. The Company is obligated to pay tiered royalties, based on licensing agreements acquired with the Bile Acid Medicines, with rates ranging from high single digit to mid-teens based on net sales of the Bile Acid Medicines. Assignment and License Agreement with Shire International GmbH (Takeda) In November 2018, the Company entered into an Assignment and License Agreement (the “Shire Agreement”) with Shire International GmbH (“Shire”), which was subsequently acquired by Takeda Pharmaceutical Company Limited (“Takeda”). Under the terms of the Shire Agreement, Shire granted the Company an exclusive, royalty bearing worldwide license to develop and commercialize its two product candidates, Livmarli and volixibat. As part of the Shire Agreement, the Company was assigned license agreements held by Shire with Satiogen Pharmaceuticals, Inc. (“Satiogen”), Pfizer Inc. (“Pfizer”) and Sanofi-Aventis Deutschland GmbH (“Sanofi”). The Company has the right to sublicense under the Shire Agreement and additionally has the right to sublicense under the Satiogen, Pfizer and Sanofi licenses subject to the terms of those license agreements. The Company is obligated to pay Shire up to an aggregate of $109.5 million upon the achievement of certain clinical development and regulatory milestones for Livmarli in certain indications and an additional $25.0 million upon regulatory approval of Livmarli for each and every other indication. In addition, the Company is required to pay up to an aggregate of $30.0 million upon the achievement of certain clinical development and regulatory milestones for volixibat solely for the first indication sought. Upon commercialization, the Company is obligated to pay Shire product sales milestones on total licensed products up to an aggregate of $30.0 million. The Company is also obligated to pay tiered royalties with rates ranging from low double-digits to mid-teens based upon annual worldwide net sales for all licensed products; however, these royalties are reduced in part by royalties due under the Satiogen and Sanofi licenses, as discussed below, related to Livmarli and volixibat, as applicable. The Company’s royalty obligations will continue on a licensed product-by-licensed product and country-by-country basis until the later to occur of the expiration of the last valid claim in a licensed patent covering the applicable licensed product in such country, expiration of any regulatory exclusivity for the licensed product in a country and ten years after the first commercial sale of a licensed product in such country. In January 2023, the Company paid the accrued regulatory milestone of $15.0 million associated with approval of Livmarli by the European Commission for the treatment of cholestatic pruritus in patients with ALGS two months of age and older. As of March 31, 2024, the Company accrued $10.0 million associated with the approval of Livmarli for the treatment of cholestatic pruritus in patients with PFIC five years of age and older by the FDA. The accrued milestone was paid in April 2024 . Satiogen License Through the Shire Agreement, the Company was assigned a license agreement with Satiogen pursuant to which the Company obtained an exclusive, worldwide license to certain patents and know-how, with the right to sublicense to a third party subject to certain financial considerations. Pursuant to the terms of the license agreement, the Company was obligated to pay to Satiogen up to an aggregate of $10.5 million upon the achievement of certain milestones, of which $0.5 million was for initiation of certain development activitie s, $5.0 million for the completion of regulatory approvals and $5.0 million for commercialization activities. Additionally, the Company was required to pay a low single-digit royalty on net sales. The Company’s royalty obligations continued on a licensed product-by-licensed product and country-by-country basis until the expiration of the last valid claim in a licensed patent covering the applicable licensed product in such country. Royalty obligations under the Satiogen license were creditable against the royalty obligations to Shire under the Shire Agreement. The Company has not paid milestone payments pursuant to this agreement for the periods presented. In May 2022, the Company completed the merger and acquisition of Satiogen for total consideration of approximately $24.2 million. At acquisition, Satiogen’s assets consisted of cash and intangible assets related to developed technology. The purchase consideration consisted of 609,305 shares of the Company’s common stock issued upon the closing of the acquisition and cash consideration of $2.6 million, with up to an additional 32,494 shares of common stock that would have been issued upon the closing of the acquisition except the parties agreed to such shares being held back by the Company for 12 months from the acquisition date to satisfy certain purchase price adjustments and indemnification obligations that may arise during this period. The purchase consideration also included issuance of up to an additional 199,993 shares of the Company’s common stock, contingent upon the achievement of a certain milestone by June 30, 2025. In December 2022, with the approval of Livmarli by the European Commission for the treatment of cholestatic pruritus in patients with ALGS two months of age and older, the milestone was achieved and the Company issued 199,993 shares of common stock in January 2023. Additionally, in June 2023, the contingencies related to the held back shares were resolved and the Company issued 31,631 shares of common stock. Through the transaction, the Company obtained all Satiogen licensing payments and Satiogen-owned intellectual property relating to Livmarli and volixibat. The transaction resulted in a reduction of total licensing royalty obligations for Livmarli and volixibat. Pfizer License Through the Shire Agreement, the Company was assigned a license agreement with Pfizer pursuant to which the Company obtained an exclusive, worldwide license to certain Pfizer know-how with a right to sublicense. Upon commercialization of any product utilizing the licensed product, the Company will be required to pay to Pfizer a low single-digit royalty on net sales of product sold by the Company, its affiliates or sublicensees. The Company’s royalty obligations continue on a licensed product-by-licensed product basis until the eighth anniversary of the first commercial sale of such licensed product anywhere in the world. Sanofi License Through the Shire Agreement, the Company was assigned a license agreement with Sanofi pursuant to which the Company obtained an exclusive, worldwide license to certain patents and know-how with the right to sublicense to a third party subject to certain financial considerations. The Company is obligated to pay up to an aggregate of $36.0 million upon the achievement of certain regulatory, commercialization and product sales milestones. Additionally, upon commercialization, the Company is required to pay tiered royalties in the mid to high single-digit range based upon net sales of licensed products sold by the Company and sublicensees in a calendar year, subject to adjustments in certain circumstances. The Company’s royalty obligations continue on a licensed product-by-licensed product and country-by-country basis until the later to occur of the expiration of the last valid claim in a licensed patent covering the applicable licensed product in such country and ten years after the first commercial sale of a licensed product in such country. Royalty obligations under the Sanofi license are creditable against the royalty obligations to Shire under the Shire Agreement. The Company has not paid milestone payments pursuant to this agreement for the periods presented. As of March 31, 2024, no milestones had been accrued as there were no potential milestones considered probable.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	Collaboration and License Agreements License and Collaboration Agreement with CANbridge In April 2021, the Company entered into an exclusive license and collaboration agreement with CANbridge Pharmaceuticals, Inc. (“CANbridge”), as amended in March 2024. Under the terms of the agreement, CANbridge has obtained the exclusive right to develop and commercialize Livmarli within the Greater China regions (China, Hong Kong, Macau and Taiwan). In connection with the agreement, the Company received an upfront payment of $11.0 million, which, upon satisfaction of the performance obligation and receipt by CANbridge of the right to use and benefit from the license in May 2021, was recorded as license revenue. Additionally, the Company is eligible to receive up to $5.0 million in research and development funding, and up to $109.0 million for the achievement of future regulatory and commercial milestones, with double-digit tiered royalties based on product net sales. Research and development funding payable by CANbridge to the Company which is reflected as a reduction of research and development expense in the accompanying unaudited condensed consolidated statements of operations for the three months ended March 31, 2024 and 2023 was insignificant. Research and development funding recorded as a receivable which was included in accounts receivable on the accompanying unaudited condensed consolidated balance sheets as of March 31, 2024 and December 31, 2023 was insignificant. License and Collaboration Agreement with GC Biopharma In July 2021, the Company entered into an exclusive license and collaboration agreement with GC Biopharma. Under the terms of the agreement, GC Biopharma has obtained the exclusive right to develop and commercialize Livmarli within South Korea for ALGS, PFIC, and biliary atresia (“BA”). In connection with the agreement, the Company received a $5.0 million upfront payment, which, upon satisfaction of the performance obligation and receipt by GC Biopharma of the right to use and benefit from the license, was recorded as license revenue. Additionally, the Company is entitled to certain research and development funding and up to $23.0 million for the achievement of future regulatory and commercial milestones, with double-digit tiered royalties based on product net sales. In February 2023, GC Biopharma achieved a regulatory milestone under this agreement triggering a milestone payment to the Company of $2.5 million, which upon the release of the constraint was included in the transaction price and recognized as license revenue in the accompanying unaudited condensed consolidated statements of operations for the three months ended March 31, 2023. For the three months ended March 31, 2024 and 2023, research and development funding payable by GC Biopharma to the Company was insignificant and was reflected as a reduction of research and development expense in the accompanying unaudited condensed consolidated statements of operations. As of March 31, 2024 and December 31, 2023, such research and development funding included in accounts receivable on the accompanying unaudited condensed consolidated balance sheets was insignificant. Licensing Agreement with Takeda In September 2021, the Company entered into an exclusive licensing agreement with Takeda for the development and commercialization of Livmarli in Japan for ALGS, PFIC, and BA. Under the terms of the agreement, Takeda will be responsible for regulatory approval and commercialization of Livmarli in Japan. Takeda will also be responsible for development, including conducting clinical studies in cholestatic indications. The Company is responsible for commercial supply to Takeda. In exchange, the Company is eligible to receive a percentage of Takeda’s annualized net sales, which range from high double digits declining to mid double digits over the first four years from commercial launch and thereafter remains at mid double digits. The Company fully constrained all revenues upon transfer of control of the license to Takeda, which occurred when Takeda could use and benefit from the license, and will recognize any consideration related to sales-based payments when the related sales occur, as the Company has determined that these amounts relate predominantly to the license granted and therefore will be recognized on the later to occur of satisfaction of the performance obligation or the occurrence of the related sales.

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases	Leases In January 2019, the Company entered into an operating lease agreement for office space which consisted of approximately 5,600 square feet (the “Initial Lease”). The lease term is approximately four years with an option to extend the term for one five-year term, which at the time was not reasonably assured of exercise and therefore, not included in the lease term. The lease contained a tenant improvement allowance of $0.4 million, which has been recorded as leasehold improvements on the accompanying unaudited condensed consolidated balance sheets with a corresponding reduction of the right-of-use (“ROU”) asset at inception of the lease. Rent payments commenced in August 2019. In November 2019, the Company amended the operating lease agreement (the “Amended Agreement”) to extend the term of the Initial Lease through March 2025. This extension was accounted for as a lease modification. Additionally, pursuant to the Amended Agreement, the Company expanded the office space by 5,555 square feet for a five-year term expiring in March 2025 (the “Expanded Space”). The Company accounted for the Expanded Space as a separate contract as there were material additional rights of use that were not included in the Initial Lease. The Amended Agreement contained a tenant improvement allowance of $0.8 million in connection with the expanded space, which has been recorded as leasehold improvements within property and equipment, net on the accompanying unaudited condensed consolidated balance sheets with a corresponding reduction of the ROU asset at inception of the lease for the expanded space. In January 2024, the Company entered into an operating lease agreement for approximately 36,300 square feet of office space (the “New Lease”). The lease term is approximately five years and the Company will be paying approximately $10.8 million in base rent during the term. The Company expects the New Lease to commence in the second quarter of 2024. Concurrently with entering into the New Lease, the Company entered into an amendment of its existing Amended Agreement to accelerate the lease expiration date from March 2025 to shortly after the commencement date of the New Lease. The following tables contain a summary of other information and the undiscounted future minimum payments pertaining to the Company’s operating leases that commenced as of the end of the periods presented: As of March 31, 2024 2023 Weighted-average incremental borrowing rate 8.0 % 8.0 % Weighted-average remaining lease term (in years) 2.9 years 1.9 years Undiscounted Rent Payments as of March 31, 2024 (in thousands) 2024 (remaining nine months) $ 350 2025 127 2026 114 2027 114 2028 57 Thereafter — Total undiscounted lease payments 762 Less: imputed interest (76) Total lease liability $ 686 Rent expense was $0.3 million and $0.2 million for the three months ended March 31, 2024 and 2023, respectively. Variable lease payments for operating expenses for the three months ended March 31, 2024 and 2023 were insignificant.

Convertible Notes

Convertible Notes	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Convertible Notes	Convertible Notes Except as described below the Company’s convertible notes are described in Note 10 of the “Notes to Consolidated Financial Statements” in the Annual Report. The convertible notes consisted of the following (in thousands): March 31, 2024 December 31, 2023 Principal amount $ 316,250 $ 316,250 Unamortized debt discount and issuance costs (9,415) (9,829) Net carrying amount $ 306,835 $ 306,421 The Company incurred $10.9 million of transaction costs related to the issuance of the 4.00% Convertible Senior Notes due 2029 (the “Notes”), which are being amortized to interest expense over the term of the Notes using the effective interest method. As of March 31, 2024, the remaining amortization period of the debt discount was approximately 5.1 years and the effective interest on the Notes was 4.6%. The following table sets forth interest expense recognized related to the Notes (in thousands): Three Months Ended March 31, 2024 Coupon interest expense $ 3,163 Amortization of debt discount and issuance costs 414 Total interest expense on convertible notes $ 3,577 As of March 31, 2024 and December 31, 2023, the estimated fair value of the Notes was $357.8 million and $387.3 million, respectively. The fair values were determined based on the quoted price of the convertible notes in an inactive market on the last trading day of the reporting period and has been classified as Level 2 in the fair value hierarchy.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Common Stock In August 2020, the SEC declared effective a registration statement on Form S-3 (“2020 Shelf Registration”) covering the sale of up to $300.0 million of the Company’s securities. Also, in August 2020, the Company entered into a sales agreement (“2020 Sales Agreement”) with SVB Securities LLC, recently acquired by Leerink Partners LLC (“Leerink”) pursuant to which the Company could elect to issue and sell, from time to time, shares of common stock having an aggregate offering price of up to $75.0 million under the 2020 Shelf Registration through Leerink acting as the sales agent and/or principal. During the three months ended March 31, 2023, the Company issued and sold 658,206 shares of common stock pursuant to the 2020 Sales Agreement resulting in gross proceeds to the Company of $15.0 million. The net proceeds to the Company for the three months ended March 31, 2023, after deducting sales commissions to Leerink and other issuance expenses were approximately $14.5 million. The Company has issued and sold an aggregate of 2,125,090 shares of common stock pursuant to the 2020 Sales Agreement resulting in aggregate gross proceeds to the Company of $43.7 million. The 2020 Shelf Registration expired in August 2023, and no further sales may be made under the 2020 Sales Agreement. On September 9, 2022, the Company filed an automatic shelf registration statement on Form S-3 with the SEC (the “2022 Shelf Registration”), which became effective upon filing, pursuant to which the Company registered for sale from time to time in one or more offerings an unlimited amount of any combination of the Company’s common stock, preferred stock, debt securities and warrants, so long as the Company continues to satisfy the requirements of a “well-known seasoned issuer” under SEC rules. This automatic shelf registration statement will remain in effect for up to three years from the date it became effective. As of March 31, 2024, the Company had not issued any securities pursuant to the automatic shelf registration statement. On August 31, 2023, 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, which the Company used to finance the upfront payment at the closing of the Bile Acid Portfolio Acquisition. On November 2, 2023, the Company entered into a Sales Agreement (the “2023 Sales Agreement”) with Leerink and Cantor Fitzgerald & Co. (the “Sales Agents”), pursuant to which the Company may, from time to time, sell up to an aggregate amount of $200.0 million of its common stock through the Sales Agents in an “at-the-market” offering (the “ATM Offering”). The Company is not required to sell shares under the 2023 Sales Agreement. Sales of the Company’s common stock, if any, under the 2023 Sales Agreement may be made in any transactions that are deemed to be “at the market offerings” as defined in Rule 415 under the Securities Act. The Company will pay a given designated Sales Agent a commission of up to 3.0% of the aggregate gross proceeds of any shares of common stock sold through such Sales Agent pursuant to the 2023 Sales Agreement. As of March 31, 2024, the Company had not issued any securities pursuant to the 2023 Sales Agreement. Common Stock Reserved for Issuance Common stock reserved for issuance is as follows: As of March 31, As of December 31, Stock options, restricted stock units and performance stock units issued and outstanding 12,525,389 10,909,831 Reserved for future stock awards or option grants 2,612,900 2,230,264 Reserved for employee stock purchase plan 1,508,059 1,040,828 Common stock issuable upon conversion of convertible notes 9,964,247 9,964,247 26,610,595 24,145,170

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Equity Incentive Plans In November 2018, the Company adopted the 2018 Equity Incentive Plan (the “2018 Plan”), which permits the granting of stock awards and incentive and nonstatutory stock options to employees, directors and consultants of the Company. In July 2019, the Company’s board of directors and stockholders approved and adopted the 2019 Equity Incentive Plan (the “2019 Plan”). The 2019 Plan became effective on July 17, 2019. Under the 2019 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units and other stock or cash-based awards to individuals who are then employees, officers, directors or consultants of the Company. Shares subject to outstanding awards under the 2018 Plan as of the effective date of the 2019 Plan that are subsequently canceled, forfeited or repurchased by the Company will be added to the shares reserved under the 2019 Plan. In addition, the number of shares of common stock available for issuance under the 2019 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2019 Plan, beginning with January 1, 2020 and ending with January 1, 2029, by an amount equal to 5% of the outstanding number of shares of the Company’s common stock on December 31st of the preceding calendar year or such lesser amount as determined by the Company’s board of directors. As of March 31, 2024, 1,721,899 shares of common stock were available for issuance under the 2019 Plan. In March 2020, the compensation committee of the Company’s board of directors approved and adopted the 2020 Inducement Plan (the “2020 Inducement Plan”). Under the 2020 Inducement Plan, the Company may grant nonstatutory stock options, stock appreciation rights, restricted stock and restricted stock units to new employees entering into employment with the Company in accordance with Nasdaq Listing Rule 5635(c)(4). At adoption, the 2020 Inducement Plan authorized 750,000 shares of the Company’s common stock for future issuance. Through March 31, 2024, the Company’s board of directors authorized an additional 3,250,000 shares of the Company’s common stock for future issuance. As of March 31, 2024, 891,001 shares of common stock were available for issuance under the 2020 Inducement Plan. Stock Options The following table summarizes stock option activity during the three months ended March 31, 2024 (in thousands, except share and per share data): Number of Awards Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in Years) Aggregate Intrinsic Value Outstanding as of December 31, 2023 9,632,504 $ 15.87 6.9 $ 131,785 Granted 1,414,439 $ 26.56 Exercised (73,309) $ 16.31 Canceled and forfeited (139,901) $ 22.44 Outstanding as of March 31, 2024 10,833,733 $ 17.18 7.0 $ 90,813 Vested and exercisable as of March 31, 2024 6,523,254 $ 12.90 5.8 $ 79,722 Intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that had exercise prices that were lower than the per share fair value of the common stock on the date of exercise. The weighted-average grant date fair value per share of stock options granted during the three months ended March 31, 2024 and 2023 was $19.01 and $16.81 per share, respectively. The total intrinsic value of options exercised during the three months ended March 31, 2024 and 2023 was $0.7 million and $0.5 million, respectively. As of March 31, 2024, the total unrecognized stock-based compensation related to unvested stock option awards granted was $66.0 million, which the Company expects to recognize over a weighted-average period of approximately 2.9 years. The fair value of each employee and non-employee stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. Due to the Company’s limited operating history and a lack of company specific historical and implied volatility data, the expected stock price volatility was based upon the weighting of the Company’s historical volatility and the historical volatility of a peer group of publicly traded companies. The historical volatility data was computed using the daily closing prices for the Company’s and its peer companies’ shares during the equivalent period of the calculated expected term of the stock-based awards. Due to the lack of historical exercise history, the expected term of the Company’s stock options for employees has been determined utilizing the “simplified” method for awards. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is zero based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The following assumptions were used to estimate the fair value of stock option awards granted during the following periods: Three Months Ended March 31, 2024 2023 Expected term (in years) 6.08 5.31-6.08 Expected volatility 78.21% - 80.36% 81.83%-85.24% Risk-free interest rate 3.82% - 4.16% 3.61%-3.91% Expected dividend yield — — Restricted Stock Units The following table summarizes the activity under the Company’s restricted stock units for the three months ended March 31, 2024: Number of Weighted-Average Grant Date Unvested and outstanding as of December 31, 2023 1,129,492 $ 23.41 Granted 576,495 $ 26.58 Vested (261,009) $ 20.46 Cancelled/Forfeited (53,407) $ 24.39 Unvested and outstanding as of March 31, 2024 1,391,571 $ 25.24 The fair value of restricted stock unit awards granted to employees and nonemployees is equal to the closing market price of the Company’s common stock on the grant date. As of March 31, 2024, the total unrecognized stock-based compensation related to restricted stock unit awards granted was $30.4 million, which the Company expects to recognize over a weighted-average period of approximately 2.1 years. Performance Stock Units In January 2023, the Company granted an aggregate of 135,835 performance stock units to certain executive participants (“2023 Executive PSUs”). The 2023 Executive PSUs are subject to a performance condition of achieving certain net product sales levels related to Livmarli during the year ended December 31, 2024. If the performance condition is met, the first tranche of the award will vest on March 15, 2025 and the second tranche will vest on March 15, 2026, subject to the executive employees’ continuous service through each vesting date. The number of units to be vested in the first tranche of the 2023 Executive PSUs is calculated by multiplying two-thirds of the 2023 Executive PSUs granted by a percentage calculated based on attained Livmarli sales metrics, as certified by the Company’s Compensation Committee. The number of units to be vested in the second tranche of the 2023 Executive PSUs equals 50% of the units vested in the first tranche. In June 2023, the Company granted an aggregate of 12,000 PSUs to certain employees (“2023 Employee PSUs”). The 2023 Employee PSUs are subject to a performance condition of achieving certain net product sales related to Livmarli in the US for the year ended December 31, 2023. The first tranche of the 2023 Employee PSUs vested during the three months ended March 31, 2024. In January 2024, the Company granted an aggregate of 148,250 performance stock units to certain executive participants (“2024 Executive PSUs”). The 2024 Executive PSUs are subject to a performance condition of achieving certain net product sales levels related to the Company’s approved medicines during the year ended December 31, 2025. If the performance condition is met, the first tranche of the award will vest on March 15, 2026 and the second tranche will vest on March 15, 2027, subject to the executive employees’ continuous service through each vesting date. The number of units to be vested in the first tranche of the 2024 Executive PSUs is calculated by multiplying two-thirds of the 2024 Executive PSUs granted by a percentage calculated based on attained sales metrics for the Company’s approved medicines, as certified by the Company’s Compensation Committee. The number of units to be vested in the second tranche of the 2024 Executive PSUs equals 50% of the units vested in the first tranche. The following table summarizes the activity under the Company's performance stock units for the three months ended March 31, 2024: Number of Weighted-Average Grant Date Unvested and outstanding as of December 31, 2023 147,835 $ 23.64 Granted 160,250 $ 26.49 Vested (3,645) $ 25.39 Cancelled/Forfeited (4,355) $ 25.39 Unvested and outstanding as of March 31, 2024 300,085 $ 25.11 As of March 31, 2024, the total unrecognized stock compensation related to performance stock units granted was $6.7 million, which the Company expects to recognize over a weighted-average period of approximately 2.0 years. 2019 Employee Stock Purchase Plan In July 2019, the Company’s board of directors and stockholders approved and adopted the 2019 Employee Stock Purchase Plan (“ESPP”). A total of 500,000 shares of common stock were approved to be initially reserved for issuance under the ESPP. In addition, the number of shares of common stock available for issuance under the ESPP will be automatically increased on the first day of each calendar year during the first ten years of the term of the ESPP, beginning with January 1, 2020 and ending with January 1, 2029, by an amount equal to the lesser of (i) 1% of the outstanding number of shares of common stock on December 31st of the preceding calendar year, (ii) 1,500,000 shares of common stock or (iii) such lesser amount as determined by the Company’s board of directors. The ESPP became effective on July 17, 2019 and generally provides for six-month consecutive offering periods beginning on May 11th and November 11th of each year. During the three months ended March 31, 2024, no shares were issued under the ESPP. As of March 31, 2024, the Company had 1,508,059 shares available for future issuance under the ESPP. The stock-based compensation related to the ESPP was $0.3 million for each of the three months ended March 31, 2024 and 2023. Compensation Expense Total stock-based compensation is reflected in the accompanying unaudited condensed consolidated statements of operations as follows (in thousands): Three Months Ended March 31, 2024 2023 Selling, general and administrative $ 7,589 $ 5,846 Research and development 3,861 2,715 Total $ 11,450 $ 8,561 Stock-based compensation capitalized into inventory was $0.2 million for each of the three months ended March 31, 2024 and 2023.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Certain of the Company's contractual arrangements with contract manufacturing organizations require binding forecasts or commitments to purchase minimum amounts for the manufacture of drug product supply, which may be material to the Company's unaudited condensed financial statements. The Company is subject to potential liabilities under government regulations and various claims and legal actions that are pending or may be asserted from time-to-time. These matters arise in the ordinary course and conduct of the Company’s business and may include, for example, commercial, intellectual property, and employment matters. The Company intends to defend itself vigorously in such matters and when warranted, take legal action against others. Furthermore, the Company regularly assesses contingencies to determine the degree of probability and range of possible loss for potential accrual in its unaudited condensed consolidated financial statements. An estimated loss contingency is accrued in the Company’s unaudited condensed consolidated financial statements if it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. The Company does not accrue amounts for liabilities that it does not believe are probable. Litigation is inherently unpredictable, and unfavorable resolutions could occur. As a result, assessing contingencies is highly subjective and requires judgment about future events. During the periods presented, the Company has not recorded any accrual for loss contingencies associated with such government regulations, claims or legal actions, determined that an unfavorable outcome is probable or reasonably possible, or determined that the amount or range of any possible loss is reasonably estimable.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, the accompanying unaudited condensed consolidated financial statements do not include all of the information and notes required by GAAP for complete financial statements. The unaudited interim financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The unaudited condensed consolidated balance sheet as of December 31, 2023 has been derived from the audited consolidated financial statements at that date but does not include all information and footnotes required by GAAP for complete financial statements. The operating results presented in these unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto in the Company’s Annual Report on Form 10-K (“Annual Report”) for the fiscal year ended December 31, 2023, as filed with the SEC on March 15, 2024.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the financial statements and accompanying notes. These estimates and assumptions are based upon historical experience, knowledge of current events and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results could differ materially from those estimates. The Company’s unaudited condensed consolidated financial statements as of and for the three months ended March 31, 2024 reflect the Company’s estimates of the impact of the geopolitical and macroeconomic environment, including the impact of inflation, bank failures, high interest rates and foreign exchange rate fluctuations. The duration and the scope of these conditions cannot be predicted; therefore, the extent to which these conditions will directly or indirectly impact the Company’s business, results of operations and financial condition, is uncertain. The Company is not aware of any specific event or circumstance that would require an update to its estimates, judgments and assumptions or a revision of the carrying value of the Company’s assets or liabilities as of the date of this filing.
Cash, Cash Equivalents and Restricted Cash Equivalents	Cash, Cash Equivalents and Restricted Cash Equivalents The Company considers all highly liquid investments that are readily convertible into cash without penalty and with original maturities of three months or less at the date of purchase to be cash equivalents. The carrying amounts reported in the unaudited condensed consolidated balance sheets for cash and cash equivalents are valued at cost, which approximate their fair value. Restricted cash equivalents as of March 31, 2023 consisted of deposits placed in a segregated bank account as required under the terms of the Company’s Revenue Interest Purchase Agreement (“RIPA”), as amended September 2021 and March 2022, with Mulholland SA LLC, an affiliate of Oberland Capital LLC, as agent for the purchasers party thereto (the “Purchasers”), and the Purchasers in connection with the sale of the Priority Review Voucher in December 2022. Upon repurchase and the termination of the RIPA in April 2023, in accordance with its terms, the previously restricted cash equivalents of $100.0 million were no longer restricted from use.
Investments	Investments The Company classifies all investments in securities as available-for-sale. Management determines the appropriate classification of its investments in securities at the time of purchase. Investments with original maturities beyond three months at the date of purchase and which mature at, or less than twelve months from the balance sheet date, are classified as a current asset. Investments are recorded at fair value, with unrealized gains and losses reported as accumulated other comprehensive income (loss) until realized, with the exception of any declines in fair value below the cost basis that are a result of a credit loss, which, if any, are reported in other income (expense), net in the current period through an allowance for credit losses. Each reporting period, the Company evaluates whether declines in fair values of its available-for-sale securities below their cost basis are a result of credit loss or other factors and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss, the creditworthiness of the security issuers, as well as the Company’s ability and intent to hold the available-for-sale security until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any available-for-sale securities before recovery of its amortized cost basis. The cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion, as well as interest and dividends, are included in interest income. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis and are also included in Other income (expense). To date, the Company has not identified any declines in fair value of its investments related to credit loss.
Concentrations of Credit Risk and Off-Balance Sheet Risk	Concentrations of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, accounts receivable and investments. The Company limits the amount of credit exposure by investing cash that is not required for immediate operating needs in money market funds, government obligations and/or commercial paper with short maturities. Additionally, the Company has established guidelines regarding diversification of its investments and their maturities, which are designed to maintain principal and maximize liquidity. To date, the Company has not experienced any losses associated with this credit risk and continues to believe that this exposure is not significant. The Company relies on a single distributor and a specialty pharmacy for all of the Company’s sales of its approved medicines in the United States as well as a single distributor for sales of Livmarli outside the United States. The Company sources materials and services through several vendors. Certain materials are sourced from a single vendor. The loss of certain vendors could result in a temporary disruption of the Company’s commercialization efforts. As of March 31, 2024 and as of December 31, 2023, the Company did not have any customers that individually accounted for more than 10% of accounts receivable. For the three months ended March 31, 2024 and 2023, the Company did not have revenue attributable to any one customer in excess of 10% of sales.
Accounts Receivable	Accounts Receivable The Company has accounts receivable amounts due from product sales. The Company also has accounts receivable amounts due from license agreements for milestones achieved, but not yet paid. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company estimates the allowance for credit losses using the current expected credit loss model. Under this model, the allowance for credit losses reflects the Company’s estimate of lifetime expected credit losses. The Company evaluates the collectability of the cash flows based on the risk of loss over the contractual life, even when that risk is remote, based on judgments about the creditworthiness of its customers, historical experience and other relevant information that is available to the Company. There was no allowance for credit losses as of March 31, 2024. There was no bad debt expense for the three months ended March 31, 2024 and 2023.
Inventory	Inventory Inventory is valued at the lower of cost or net realizable value, with cost determined on a first-in, first-out (FIFO) basis. The Company periodically reviews the composition of inventory to identify excess, obsolete, slow-moving or otherwise unsaleable items. If unsaleable items are observed and there are no alternate uses for the inventory, the Company will record a write-down to net realizable value in the period that the decline in value is recognized through a charge to cost of sales. Furthermore, the Company periodically reviews its firm commitments for the purchase of minimum order quantities. If the minimum order quantities exceed the Company’s future demand, a net loss is accrued in cost of sales for such future inventory purchases. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required.
Intangibles Assets, Net	Intangible Assets, Net The Company accounts for asset acquisitions that do not meet the definition of a business using the cost accumulation method, whereby the cost of the acquisition, including certain transaction costs, is allocated to the asset (or assets) acquired on the basis of its (or their) relative fair value(s) on the measurement date. No goodwill is recognized in an asset acquisition. Intangible assets are measured at their fair values as of the acquisition date or, in the case of commercial milestone payments, the date they become due. The evaluation of intangible assets includes assessing the amortization period for which the asset is expected to contribute to the future cash flows of the Company. Intangible assets with finite useful lives are amortized over their estimated useful lives, primarily on a straight-line basis when the Company is unable to reliably estimate the pattern of cash flow. The Company tests its finite lived intangible assets for impairment annually or if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. If it is determined that the asset is impaired, the carrying value is written down to its estimated fair value, with the related impairment charge recognized in the unaudited condensed consolidated statements of operations in the period in which the impairment occurs. The Company has not recorded any impairments to its intangible assets for any of the periods presented. The components of the Company’s intangible assets were as follows (in thousands, except for weighted-average remaining amortization period): March 31, 2024 Gross Carrying Value Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Amortization Period (Years) Commercial milestones $ 49,000 $ (3,968) $ 45,032 14.3 Developed technology 226,620 (14,991) 211,629 11.4 Assembled workforce 970 (188) 782 2.4 Total intangible assets $ 276,590 $ (19,147) $ 257,443 11.9 December 31, 2023 Gross Carrying Value Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Amortization Period (Years) Commercial milestones $ 39,000 $ (3,318) $ 35,682 16.2 Developed technology 226,620 (10,239) 216,381 11.7 Assembled workforce 970 (108) 862 2.7 Total intangible assets $ 266,590 $ (13,665) $ 252,925 12.3 Amortization expense was $5.5 million and $1.3 million for the three months ended March 31, 2024 and 2023, respectively. Amortization expense was included in cost of sales in the accompanying unaudited condensed consolidated statements of operations. The following table summarizes the estimated future amortization expense associated with the Company’s intangible assets as of March 31, 2024 (in thousands): Amount 2024 (remaining nine months) 17,023 2025 22,698 2026 22,590 2027 22,375 2028 22,375 Thereafter 150,382 $ 257,443
Product Sales, Net	Product Sales, Net The Company recognizes product sales, net when the customer obtains control of our product, which occurs at a point in time, typically upon delivery of the Company’s product to the customer. Revenues from product sales are recorded at the net sales price, or the transaction price, which may include fixed or variable consideration for discounts, government rebates, co-pay assistance, returns and other allowances that are offered within contracts with a customer relating to the sale of the Company's approved medicines. Estimates of variable consideration are calculated based on the actual product sales each reporting period and the nature of the variable consideration related to those sales. Overall, these estimates reflect the Company’s best estimate of the amount of consideration to which the Company expects to be entitled based on the terms of the contract. The amount of variable consideration that is included in the transaction price may be constrained and is included in product sales, net only to the extent that it is considered probable that a significant reversal in the amount of the cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Estimates are reviewed and updated quarterly as additional information becomes known. Actual amounts of consideration ultimately received may differ materially from estimates. If actual results in the future vary from estimates, the Company will adjust these estimates, which would affect product sales, net and earnings in the period such variances are adjusted. Significant categories of sales discounts and allowances are as follows: Government Rebates : The Company records rebates payable under Medicaid and other government programs as a reduction of revenue at the time product revenues are generated. The Company’s rebate calculations may require estimates, including estimates of customer mix, to determine which sales will be subject to rebates and the amount of such rebates. The Company updates its estimates and assumptions on a quarterly basis and records any necessary adjustments to revenue in the period identified. The liability for unpaid rebates is included in accrued expenses on the accompanying unaudited condensed consolidated balance sheets. To date, actual government rebates have not differed materially from the Company’s estimates. Other Incentives : Other incentives include a branded co-pay assistance program for eligible patients with commercial insurance in the United States. The branded co-pay assistance program assists commercially insured patients who have coverage for the Company's approved medicines and is intended to reduce each participating patient’s portion of the financial responsibility of the purchase price up to a specified dollar amount of assistance. The calculation of the accrual for co-pay assistance is based upon an identification of claims and the cost per claims associated with product that has been recognized as revenue. The Company records amounts paid under the brand specific co-pay assistance program for each patient as a reduction of revenue from product sales. To date, actual other incentives have not differed materially from the Company’s estimates. Product Returns : The Company records revenue for product sales, net of estimated product returns. Customers have limited return rights related only to the product’s damage or defect identified upon delivery of the product. The Company estimates the amount of product sales that may be returned and records the estimate as a reduction of revenue and a refund liability in the period the related product revenue is recognized. To date, actual returns have not differed materially from the Company’s estimates. The following table represents Total revenues and disaggregates Product sales, net by approved medicine (in thousands): Three Months Ended March 31, 2024 2023 Product sales, net: Livmarli $ 42,845 $ 29,098 Bile Acid Medicines 26,072 — Total product sales, net 68,917 29,098 License and other revenue 305 2,500 Total revenues $ 69,222 $ 31,598
Foreign Currency	Foreign Currency The unaudited condensed consolidated financial statements are presented in U.S. dollars. The functional currency for most of the Company’s foreign subsidiaries is their local currency. Balance sheet accounts of international subsidiaries are translated at the current exchange rates as of the end of each accounting period. Income statement items are translated at average exchange rates for the period. The resulting translation adjustments are recorded as a separate component of stockholders’ equity. Foreign currency transaction gains and losses are included in other income (expense), net in the unaudited condensed consolidated statements of operations. Transaction gains and losses result primarily from fluctuations in exchange rates when intercompany receivables and payables are denominated in currencies other than the functional currency of our subsidiary that recorded the transaction. Unrealized foreign exchange gains amounted to $1.7 million for the three months ended March 31, 2024 and were insignificant for the three months ended March 31, 2023. Realized foreign exchange gains and losses were insignificant for the three months ended March 31, 2024 and 2023, respectively.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average shares of common stock outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average shares of common stock and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. Diluted net loss per share excludes the potential impact of the Company’s common stock subject to repurchase, common stock options, restricted stock units, contingently issuable employee stock purchase plan shares and common stock issuable upon conversion of convertible notes because their effect would be anti-dilutive due to the Company’s net loss. Basic and diluted net loss per share were the same for the three months ended March 31, 2024 and 2023.
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on the accompanying unaudited condensed consolidated financial statements and disclosures. In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segment Disclosures (“ASU 2023-07”). This new guidance is designed to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024 on a retrospective basis. Early adoption is permitted. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Improvements to Income Tax Disclosures (“ASU 2023-09”). This new guidance is designed to enhance the transparency and decision usefulness of income tax disclosures. The amendments of this update are related to the rate reconciliation and income taxes paid. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is currently assessing the impact that adopting this new accounting standard will have on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash Reported within the Consolidated Balance Sheets	The following table provides a reconciliation of cash, cash equivalents and restricted cash equivalents reported within the unaudited condensed consolidated balance sheets that together reflect the same amounts shown in the unaudited condensed consolidated statements of cash flows (in thousands): As of March 31, 2024 2023 Cash and cash equivalents $ 302,843 $ 49,419 Restricted cash equivalents — 100,000 Total cash, cash equivalents, and restricted cash equivalents $ 302,843 $ 149,419
Schedule of Finite Lived Intangible Assets	The components of the Company’s intangible assets were as follows (in thousands, except for weighted-average remaining amortization period): March 31, 2024 Gross Carrying Value Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Amortization Period (Years) Commercial milestones $ 49,000 $ (3,968) $ 45,032 14.3 Developed technology 226,620 (14,991) 211,629 11.4 Assembled workforce 970 (188) 782 2.4 Total intangible assets $ 276,590 $ (19,147) $ 257,443 11.9 December 31, 2023 Gross Carrying Value Accumulated Amortization Net Carrying Amount Weighted-Average Remaining Amortization Period (Years) Commercial milestones $ 39,000 $ (3,318) $ 35,682 16.2 Developed technology 226,620 (10,239) 216,381 11.7 Assembled workforce 970 (108) 862 2.7 Total intangible assets $ 266,590 $ (13,665) $ 252,925 12.3
Schedule of Estimated Future Amortization Expense Associated with Intangible Assets	The following table summarizes the estimated future amortization expense associated with the Company’s intangible assets as of March 31, 2024 (in thousands): Amount 2024 (remaining nine months) 17,023 2025 22,698 2026 22,590 2027 22,375 2028 22,375 Thereafter 150,382 $ 257,443
Schedule of Disaggregation of Total Product Sales	The following table represents Total revenues and disaggregates Product sales, net by approved medicine (in thousands): Three Months Ended March 31, 2024 2023 Product sales, net: Livmarli $ 42,845 $ 29,098 Bile Acid Medicines 26,072 — Total product sales, net 68,917 29,098 License and other revenue 305 2,500 Total revenues $ 69,222 $ 31,598
Schedule of Product Sales by Geographic Area	The following table sets forth Product sales, net by geographic area based on the ship-to location (in thousands): Three Months Ended March 31, 2024 2023 United States $ 56,111 $ 24,614 Rest of the world 12,806 4,484 Total product sales, net $ 68,917 $ 29,098
Summary of Outstanding Potentially Dilutive Shares of Common Stock Excluded from Calculation of Diluted Net Loss per Share	The following outstanding potential dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect: As of March 31, As of March 31, 2024 2023 Options to purchase common stock and restricted stock units 12,525,389 10,573,024 Common stock issuable upon conversion of convertible notes 9,964,247 — Employee stock purchase plan contingently issuable 48,297 66,658 Shares issuable as contingent consideration in connection with asset acquisition — 31,638 Total 22,537,933 10,671,320

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities to Fair Value Measurements On Recurring Basis and Level of Input Measurements	Financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements by major security type are presented in the following table (in thousands): March 31, 2024 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 281,865 $ — $ — 281,865 Total financial assets $ 281,865 $ — $ — $ 281,865 December 31, 2023 Level 1 Level 2 Level 3 Total Financial assets: Money market funds $ 278,116 $ — $ — $ 278,116 Total financial assets $ 278,116 $ — $ — $ 278,116

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Fair Value and Amortized Cost of Cash Equivalents and Available-for-sale Investments by Major Security Type	The fair value and amortized cost of cash equivalents and available-for-sale investments by major security type are presented in the following table (in thousands): March 31, 2024 Amortized Unrealized Unrealized Estimated Cash equivalents: Money market funds $ 281,865 $ — $ — $ 281,865 Total cash equivalents $ 281,865 $ — $ — $ 281,865 Classified as: Cash equivalents $ 281,865 Total cash equivalents $ 281,865 December 31, 2023 Amortized Unrealized Unrealized Estimated Cash equivalents: Money market funds $ 278,116 $ — $ — $ 278,116 Total cash equivalents $ 278,116 $ — $ — $ 278,116 Classified as: Cash equivalents $ 278,116 Total cash equivalents $ 278,116

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2024
Balance Sheet Components [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands): March 31, December 31, Raw materials $ 2,886 $ 2,998 Work in progress 10,850 9,873 Finished goods 7,870 9,441 Total inventory $ 21,606 $ 22,312
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): March 31, December 31, Accrued compensation and related benefits $ 12,040 $ 20,939 Accrued sales deductions 30,005 23,650 Accrued clinical trials 7,678 7,268 Accrued professional service fees 9,318 7,941 Accrued contract manufacturing and non-clinical costs 8,599 9,922 Accrued royalties payable 6,657 6,716 Accrued interest 5,271 2,108 Accrued milestone payment 10,000 — Total accrued expenses $ 89,568 $ 78,544

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Summary of Company’s Operating Leases	The following tables contain a summary of other information and the undiscounted future minimum payments pertaining to the Company’s operating leases that commenced as of the end of the periods presented: As of March 31, 2024 2023 Weighted-average incremental borrowing rate 8.0 % 8.0 % Weighted-average remaining lease term (in years) 2.9 years 1.9 years
Schedule of Undiscounted Future Minimum Payments under Operating Leases	Undiscounted Rent Payments as of March 31, 2024 (in thousands) 2024 (remaining nine months) $ 350 2025 127 2026 114 2027 114 2028 57 Thereafter — Total undiscounted lease payments 762 Less: imputed interest (76) Total lease liability $ 686

Convertible Notes (Tables)

Convertible Notes (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule Of Convertible Notes	The convertible notes consisted of the following (in thousands): March 31, 2024 December 31, 2023 Principal amount $ 316,250 $ 316,250 Unamortized debt discount and issuance costs (9,415) (9,829) Net carrying amount $ 306,835 $ 306,421
Schedule of Interest Expense Related to Convertible Notes	The following table sets forth interest expense recognized related to the Notes (in thousands): Three Months Ended March 31, 2024 Coupon interest expense $ 3,163 Amortization of debt discount and issuance costs 414 Total interest expense on convertible notes $ 3,577

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Common Stock Reserved for Issuance	Common stock reserved for issuance is as follows: As of March 31, As of December 31, Stock options, restricted stock units and performance stock units issued and outstanding 12,525,389 10,909,831 Reserved for future stock awards or option grants 2,612,900 2,230,264 Reserved for employee stock purchase plan 1,508,059 1,040,828 Common stock issuable upon conversion of convertible notes 9,964,247 9,964,247 26,610,595 24,145,170

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity during the three months ended March 31, 2024 (in thousands, except share and per share data): Number of Awards Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in Years) Aggregate Intrinsic Value Outstanding as of December 31, 2023 9,632,504 $ 15.87 6.9 $ 131,785 Granted 1,414,439 $ 26.56 Exercised (73,309) $ 16.31 Canceled and forfeited (139,901) $ 22.44 Outstanding as of March 31, 2024 10,833,733 $ 17.18 7.0 $ 90,813 Vested and exercisable as of March 31, 2024 6,523,254 $ 12.90 5.8 $ 79,722
Schedule of Assumptions Used to Estimate Fair Value of Stock Option Awards Granted	The following assumptions were used to estimate the fair value of stock option awards granted during the following periods: Three Months Ended March 31, 2024 2023 Expected term (in years) 6.08 5.31-6.08 Expected volatility 78.21% - 80.36% 81.83%-85.24% Risk-free interest rate 3.82% - 4.16% 3.61%-3.91% Expected dividend yield — —
Summary of RSU Activity	The following table summarizes the activity under the Company’s restricted stock units for the three months ended March 31, 2024: Number of Weighted-Average Grant Date Unvested and outstanding as of December 31, 2023 1,129,492 $ 23.41 Granted 576,495 $ 26.58 Vested (261,009) $ 20.46 Cancelled/Forfeited (53,407) $ 24.39 Unvested and outstanding as of March 31, 2024 1,391,571 $ 25.24
Summary of PSU Activity	The following table summarizes the activity under the Company's performance stock units for the three months ended March 31, 2024: Number of Weighted-Average Grant Date Unvested and outstanding as of December 31, 2023 147,835 $ 23.64 Granted 160,250 $ 26.49 Vested (3,645) $ 25.39 Cancelled/Forfeited (4,355) $ 25.39 Unvested and outstanding as of March 31, 2024 300,085 $ 25.11
Summary of Stock-based Compensation Reflected in Unaudited Condensed Consolidated Statements of Operations	Total stock-based compensation is reflected in the accompanying unaudited condensed consolidated statements of operations as follows (in thousands): Three Months Ended March 31, 2024 2023 Selling, general and administrative $ 7,589 $ 5,846 Research and development 3,861 2,715 Total $ 11,450 $ 8,561

Organization and Description _2

Organization and Description of Business (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment medicine	Dec. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Date of incorporation	May 02, 2018
Number of approved medicines | medicine	3
Number of operating segments | segment	1
Accumulated deficit	$ 581,518	$ 556,239
Cash and cash equivalents	$ 302,843	$ 286,326	$ 49,419

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Summary Of Significant Accounting Policies [Line Items]
Milestone payments	$ 10,000,000	$ 15,000,000	$ 0
Restricted cash equivalents	$ 0	100,000,000		$ 100,000,000
Investments with original maturities at date of purchase to be cash equivalents	3 months
Fair value of its investments related to credit loss	$ 0
Allowance for credit losses	0
Purchase commitments	5,300,000		5,200,000
Provision for doubtful accounts	0	0
Amortization expense	5,500,000	1,300,000
Unrealized foreign exchange losses	1,734,000	$ 0
Other Liabilities
Summary Of Significant Accounting Policies [Line Items]
Purchase commitments	$ 3,900,000		$ 3,800,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash Reported Within the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 302,843	$ 286,326	$ 49,419
Restricted cash equivalents	0		100,000	$ 100,000
Total cash, cash equivalents, and restricted cash equivalents	$ 302,843	$ 286,326	$ 149,419	$ 128,003

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule Of Finite Lived Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Summary Of Significant Accounting Policies [Line Items]
Gross Carrying Value	$ 276,590	$ 266,590
Accumulated Amortization	(19,147)	(13,665)
Net Carrying Amount	$ 257,443	$ 252,925
Weighted-Average Remaining Amortization Period (Years)	11 years 10 months 24 days	12 years 3 months 18 days
Commercial milestones
Summary Of Significant Accounting Policies [Line Items]
Gross Carrying Value	$ 49,000	$ 39,000
Accumulated Amortization	(3,968)	(3,318)
Net Carrying Amount	$ 45,032	$ 35,682
Weighted-Average Remaining Amortization Period (Years)	14 years 3 months 18 days	16 years 2 months 12 days
Developed technology
Summary Of Significant Accounting Policies [Line Items]
Gross Carrying Value	$ 226,620	$ 226,620
Accumulated Amortization	(14,991)	(10,239)
Net Carrying Amount	$ 211,629	$ 216,381
Weighted-Average Remaining Amortization Period (Years)	11 years 4 months 24 days	11 years 8 months 12 days
Assembled workforce
Summary Of Significant Accounting Policies [Line Items]
Gross Carrying Value	$ 970	$ 970
Accumulated Amortization	(188)	(108)
Net Carrying Amount	$ 782	$ 862
Weighted-Average Remaining Amortization Period (Years)	2 years 4 months 24 days	2 years 8 months 12 days

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Estimated Future Amortization Expense Associated with Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2024 (remaining nine months)	$ 17,023
2025	22,698
2026	22,590
2027	22,375
2028	22,375
Thereafter	150,382
Net Carrying Amount	$ 257,443	$ 252,925

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Schedule of Disaggregation of Total Product Sales (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Summary Of Significant Accounting Policies [Line Items]
Total revenue	$ 69,222	$ 31,598
Livmarli
Summary Of Significant Accounting Policies [Line Items]
Total revenue	42,845	29,098
Bile Acid Medicines
Summary Of Significant Accounting Policies [Line Items]
Total revenue	26,072	0
Total product sales, net
Summary Of Significant Accounting Policies [Line Items]
Total revenue	68,917	29,098
License and other revenue
Summary Of Significant Accounting Policies [Line Items]
Total revenue	$ 305	$ 2,500

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Schedule of Product Sales by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Total product sales, net	$ 69,222	$ 31,598
Product sales, net
Disaggregation of Revenue [Line Items]
Total product sales, net	68,917	29,098
Product sales, net | United States
Disaggregation of Revenue [Line Items]
Total product sales, net	56,111	24,614
Product sales, net | Rest of the world
Disaggregation of Revenue [Line Items]
Total product sales, net	$ 12,806	$ 4,484

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Shares of Common Stock Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares of stock (in shares)	22,537,933	10,671,320
Common stock issuable upon conversion of convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares of stock (in shares)	9,964,247	0
Options to purchase common stock and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares of stock (in shares)	12,525,389	10,573,024
Employee stock purchase plan contingently issuable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares of stock (in shares)	48,297	66,658
Shares issuable as contingent consideration in connection with asset acquisition
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares of stock (in shares)	0	31,638

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities to Fair Value Measurement On Recurring Basis and Level of Input Measurement (Details) - Fair Value, Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	$ 281,865	$ 278,116
Level 1
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	281,865	278,116
Level 2
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	0	0
Level 3
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	0	0
Money market funds
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	281,865	278,116
Money market funds | Level 1
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	281,865	278,116
Money market funds | Level 2
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	0	0
Money market funds | Level 3
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Total financial assets	$ 0	$ 0

Financial Instruments - Summary

Financial Instruments - Summary of Fair Value and Amortized Cost of Cash Equivalents and Available-for-sale Investments by Major Security Type (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Money market funds, estimated fair value / cash equivalents	$ 281,865	$ 278,116
Cash equivalents, amortized cost	281,865	278,116
Cash equivalents, unrealized gain	0	0
Cash equivalents, unrealized loss	0	0
Total cash equivalents	281,865	278,116
Money market funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Money market funds, amortized cost	281,865	278,116
Money market funds, estimated fair value / cash equivalents	$ 281,865	$ 278,116

Financial Instruments - Additio

Financial Instruments - Additional Information (Details)	3 Months Ended
	Mar. 31, 2023 USD ($)
Fair Value Disclosures [Abstract]
Realized gains or losses on available-for-sale investments	$ 0
Investments in continuous unrealized loss position for more than 12 months	0
Material unrealized gains or losses recognized	$ 0

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Balance Sheet Components [Abstract]
Raw materials	$ 2,886	$ 2,998
Work in progress	10,850	9,873
Finished goods	7,870	9,441
Total inventory	$ 21,606	$ 22,312

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Balance Sheet Components [Abstract]
Accrued compensation and related benefits	$ 12,040	$ 20,939
Accrued sales deductions	30,005	23,650
Accrued clinical trials	7,678	7,268
Accrued professional service fees	9,318	7,941
Accrued contract manufacturing and non-clinical costs	8,599	9,922
Accrued royalties payable	6,657	6,716
Accrued interest	5,271	2,108
Accrued milestone payment	10,000	0	$ 15,000
Total accrued expenses	$ 89,568	$ 78,544

Revenue Interest Purchase Agr_2

Revenue Interest Purchase Agreement - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Apr. 30, 2023
Mulholland SA LLC, | Revenue Interest Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Interest expense	$ 4.2
Payment on repurchase in connection with RIPA		$ 192.7
Sales
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue interest payments	$ 2.9

Asset Acquisitions - Additional

Asset Acquisitions - Additional Information (Details)		1 Months Ended
	Aug. 31, 2023 USD ($)	Jun. 30, 2023 shares	Jan. 31, 2023 USD ($) shares	May 31, 2022 USD ($) shares	Nov. 30, 2018 USD ($) productCandidate	Mar. 31, 2024 USD ($)
Asset Acquisitions [Line Items]
Common stock issued related to the held back shares (in shares) | shares		31,631
Satiogen
Asset Acquisitions [Line Items]
Payments for acquisition				$ 2,600,000
Total consideration				$ 24,200,000
Purchase consideration (in shares) | shares				609,305
Additional shares of common stock issued (in shares) | shares				32,494
Future issuance of additional common stock (in shares) | shares			199,993	199,993
Asset Purchase Agreement | Travere Therapeutics, Inc. | Bile Acid Medicines
Asset Acquisitions [Line Items]
Payments for acquisition	$ 210,400,000
Product sales milestone payments, payable	$ 235,000,000
Shire Agreement | Livmarli
Asset Acquisitions [Line Items]
Milestones accrued			$ 15,000,000
License agreement milestone amount accrued						$ 10,000,000
Shire Agreement | Shire
Asset Acquisitions [Line Items]
Product sales milestone payments, payable					$ 30,000,000
Number of product candidates | productCandidate					2
Shire Agreement | Shire | Livmarli
Asset Acquisitions [Line Items]
Milestone payments, payable					$ 109,500,000
Milestone payments, payable upon approval					25,000,000
Shire Agreement | Shire | Volixibat
Asset Acquisitions [Line Items]
Milestone payments, payable upon commercialization					30,000,000
Assigned License Agreement | Satiogen Pharmaceuticals, Inc.
Asset Acquisitions [Line Items]
Milestone payments, payable					10,500,000
Milestone payments, payable upon approval					5,000,000
Milestone payments, payable upon commercialization					5,000,000
Milestone payments, payable upon initiation					500,000
Assigned License Agreement | Sanofi-Aventis Deutschland GmbH
Asset Acquisitions [Line Items]
Milestone payments, payable					$ 36,000,000
Milestones accrued						$ 0
Royalty obligations payment period					10 years

Collaboration and License Agr_2

Collaboration and License Agreements (Additional Information) (Details) - Exclusive Licensing Agreement - Livmarli - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Jul. 31, 2021	Apr. 30, 2021	Mar. 31, 2023
CANbridge
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received		$ 11
CANbridge | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development funding received		5
Potential regulatory and commercial milestone payment to be received		$ 109
GC Biopharma
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received	$ 5
Achievement of future regulatory and commercial milestones payment			$ 2.5
GC Biopharma | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Achievement of future regulatory and commercial milestones payment	$ 23

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Jan. 31, 2024 USD ($) ft²	Nov. 30, 2019 USD ($) ft²	Jan. 31, 2019 USD ($) ft²
Lessee Lease Description [Line Items]
Area of office space | ft²					5,600
Term of lease					4 years
Term of extension of lease					5 years
Tenant improvement allowance					$ 400
Base rent to be paid	$ 762
Rent expense	$ 300	$ 200
Amended Operating Lease Agreement
Lessee Lease Description [Line Items]
Term of lease				5 years
Additional area of office space | ft²				5,555
Amended Operating Lease Agreement | Property, Plant and Equipment
Lessee Lease Description [Line Items]
Tenant improvement allowance				$ 800
New Lease Agreement
Lessee Lease Description [Line Items]
Area of office space | ft²			36,300
Term of lease			5 years
Base rent to be paid			$ 10,800

Leases - Company_s Operating Le

Leases - Company’s Operating Leases (Details)	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Weighted-average incremental borrowing rate	8%	8%
Weighted-average remaining lease term (in years)	2 years 10 months 24 days	1 year 10 months 24 days

Leases - Schedule of Undiscount

Leases - Schedule of Undiscounted Future Minimum Payments under Operating Leases (Detail) $ in Thousands	Mar. 31, 2024 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024 (remaining nine months)	$ 350
2025	127
2026	114
2027	114
2028	57
Thereafter	0
Total undiscounted lease payments	762
Less: imputed interest	(76)
Lease liability	$ 686

Convertible Notes - Schedule Of

Convertible Notes - Schedule Of Convertible Notes (Details) - Senior Notes Due At Two ThousandTwenty Nine - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Principal amount	$ 316,250	$ 316,250
Unamortized debt discount and issuance costs	(9,415)	(9,829)
Net carrying amount	$ 306,835	$ 306,421

Convertible Notes - Additional

Convertible Notes - Additional Information (Detail) - Senior Notes Due At Two ThousandTwenty Nine - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debt issuance costs	$ 10.9
Interest rate (percent)	4%
Debt instrument remaining life	5 years 1 month 6 days
Effective interest rate (as a percent)	4.60%
Convertible debt, fair value	$ 357.8	$ 387.3

Convertible Notes - Schedule _2

Convertible Notes - Schedule of Interest Expense Related to Convertible Notes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Amortization of debt discount and issuance costs	$ 414	$ 0
Senior Notes Due At Two ThousandTwenty Nine
Debt Instrument [Line Items]
Coupon interest expense	3,163
Amortization of debt discount and issuance costs	414
Total interest expense on convertible notes	$ 3,577

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		43 Months Ended
	Nov. 02, 2023	Aug. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Aug. 31, 2020
Class Of Stock [Line Items]
Maximum amount of sale covered in shelf registration statement						$ 300,000
Proceeds from issuance of shares			$ 0	$ 14,480
Bile Acid Portfolio Acquisition
Class Of Stock [Line Items]
Shares issued, public offering price per share (in dollars per share)		$ 26.25
Net proceeds from transaction		$ 202,200
Leerink Partners LLC
Class Of Stock [Line Items]
Maximum amount of offering issuance and sale covered in sales agreement						$ 75,000
Sales Agreement
Class Of Stock [Line Items]
Net proceeds from transaction	$ 200,000
Percentage of gross proceeds	3%
Common Stock | Sales Agreement
Class Of Stock [Line Items]
Number of shares issued (in shares)				658,206	2,125,090
Proceeds from issuance of shares				$ 14,500
Gross proceeds from issuance of common stock				$ 15,000	$ 43,700
Private Placement | Bile Acid Portfolio Acquisition
Class Of Stock [Line Items]
Number of shares issued (in shares)		8,000,000

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Common Stock Reserved for Issuance (Details) - shares	Mar. 31, 2024	Dec. 31, 2023
Class Of Stock [Line Items]
Common stock reserved for issuance (in shares)	26,610,595	24,145,170
Common stock issuable upon conversion of convertible notes
Class Of Stock [Line Items]
Common stock reserved for issuance (in shares)	9,964,247	9,964,247
Stock options, restricted stock units and performance stock units issued and outstanding
Class Of Stock [Line Items]
Common stock reserved for issuance (in shares)	12,525,389	10,909,831
Reserved for future stock awards or option grants
Class Of Stock [Line Items]
Common stock reserved for issuance (in shares)	2,612,900	2,230,264
Reserved for employee stock purchase plan
Class Of Stock [Line Items]
Common stock reserved for issuance (in shares)	1,508,059	1,040,828

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended				3 Months Ended		6 Months Ended	49 Months Ended
	Jul. 17, 2023	Jan. 31, 2024	Jun. 30, 2023	Jan. 31, 2023	Jul. 31, 2019	Mar. 31, 2024	Mar. 31, 2023	Jun. 30, 2023	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock approved and reserved for issuance (in shares)						26,610,595			26,610,595	24,145,170
Stock-based compensation expense						$ 11,450	$ 8,561
Share-based compensation expenses capitalized amount						$ 200	$ 200
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value (in dollars per share)						$ 19.01	$ 16.81
Stock-based compensation, Intrinsic value of options exercised						$ 700	$ 500
Total unrecognized stock-based compensation related to unvested stock option awards granted						$ 66,000			$ 66,000
Unrecognized stock-based compensation related to unvested stock, expected to recognize over weighted-average period						2 years 10 months 24 days
Expected dividend yield						0%	0%	0%
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock-based compensation related to unvested stock option awards granted						$ 30,400			30,400
Unrecognized stock-based compensation related to unvested stock, expected to recognize over weighted-average period						2 years 1 month 6 days
2023 Executive PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation related to unvested stock, expected to recognize over weighted-average period						2 years
Granted (in shares)		148,250	12,000	135,835
Award vesting rights percentage		50%		50%
Total unrecognized stock-based compensation						$ 6,700			$ 6,700
2019 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock expiration term					10 years
Percentage of annual increase in common stock available for issuance					5%
Number of common stock for future issuance (in shares)						1,721,899			1,721,899
2020 Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock for future issuance (in shares)						891,001			891,001		750,000
Number of additional common stock for future issuance (in shares)									3,250,000
2019 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock expiration term					10 years
Percentage of annual increase in common stock available for issuance					1%
Stock issued for services (in shares)					500,000
Annual increase in common stock available for issuance (in shares)					1,500,000
Stock plan offering period	6 months
Number of common stock approved and reserved for issuance (in shares)						1,508,059			1,508,059
2019 Employee Stock Purchase Plan | Executive Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense						$ 300	$ 300

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) - Stock Options - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Awards
Outstanding, beginning balance (in shares)	9,632,504
Granted (in shares)	1,414,439
Exercised (in shares)	(73,309)
Canceled and forfeited (in shares)	(139,901)
Outstanding, ending balance (in shares)	10,833,733	9,632,504
Weighted- Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 15.87
Granted, weighted-average exercise price (in dollars per share)	26.56
Weighted-average exercise price, exercised (in dollars per share)	16.31
Canceled and forfeited, weighted-average exercise price (in dollars per share)	22.44
Outstanding, ending balance (in dollars per share)	$ 17.18	$ 15.87
Outstanding, Weighted-Average Remaining Contractual Life (In Years)	7 years	6 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 90,813	$ 131,785
Number of awards, vested and exercisable (in shares)	6,523,254
Weighted-average exercise price, vested and exercisable (in dollars per share)	$ 12.90
Weighted-average remaining contractual life, vested and exercisable	5 years 9 months 18 days
Aggregate intrinsic value, vested and exercisable	$ 79,722

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Assumptions Used to Estimate Fair Value of Stock Option Awards Granted (Details) - Stock Options	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	78.21%	81.83%
Expected volatility, maximum	80.36%	85.24%
Risk-free interest rate, minimum	3.82%	3.61%
Risk-free interest rate, maximum	4.16%	3.91%
Expected dividend yield	0%	0%	0%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		5 years 3 months 21 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 29 days	6 years 29 days

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of RSU Activity (Details) - RSUs - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Awards
Unvested and outstanding, beginning balance (in shares)	1,391,571	1,129,492
Granted (in shares)	576,495
Vested (in shares)	(261,009)
Cancelled/Forfeited (in shares)	(53,407)
Unvested and outstanding, ending balance (in shares)	1,391,571	1,129,492
Weighted-Average Grant Date Fair Value per Award
Unvested and outstanding, weighted-average grant date fair value, beginning balance (in dollars per share)	$ 23.41
Granted, weighted-average exercise price (in dollars per share)	26.58
Vested, weighted-average exercise price (in dollars per share)	20.46
Cancelled/Forfeited, weighted-average grant date fair value per award (in dollars per share)	24.39
Unvested and outstanding, weighted-average grant date fair value, ending balance (in dollars per share)	$ 25.24

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of PSU Activity (Details) - Performance Stock Units	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Awards
Unvested and outstanding as of December 31, 2023 (in shares) | shares	147,835
Granted (in shares) | shares	160,250
Vested (in shares) | shares	(3,645)
Cancelled/Forfeited (in shares) | shares	(4,355)
Unvested and outstanding as of March 31, 2024 (in shares) | shares	300,085
Weighted-Average Grant Date Fair Value per Award
Unvested and outstanding, weighted average grant date fair value as of December 31, 2023 (in dollars per share) | $ / shares	$ 23.64
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	26.49
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	25.39
Cancelled/Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	25.39
Unvested and outstanding, weighted average grant date fair value as of March 31, 2024 (in dollars per share) | $ / shares	$ 25.11

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Stock-based Compensation Reflected in Unaudited Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 11,450	$ 8,561
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	7,589	5,846
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,861	$ 2,715