Ultragenyx Pharmaceutical (RARE) 10-K 19 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Feb. 13, 2025	Jun. 30, 2024
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Trading Symbol	RARE
Entity Registrant Name	Ultragenyx Pharmaceutical Inc.
Entity Central Index Key	0001515673
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		92,501,126
Entity Public Float			$ 3.7
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, $0.001 par value
Entity File Number	001-36276
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-2546083
Entity Address, Address Line One	60 Leveroni Court
Entity Address, City or Town	Novato
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94949
City Area Code	415
Local Phone Number	483-8800
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive proxy statement relating to its 2025 Annual Meeting of Stockholders, to be held on or about May 15, 2025, are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such proxy statement will be filed with the U.S. Securities and Exchange Commission within 120 days after the end of the fiscal year to which this report relates.
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	San Mateo, California
Auditor Opinion [Text Block]	Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Ultragenyx Pharmaceutical Inc. (the Company) as of December 31, 2024 and 2023, the related consolidated statements of operations, comprehensive loss, stockholders' equity and cash flows for each of the three years in the period ended December 31, 2024, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles. We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control— Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February 19, 2025 expressed an unqualified opinion thereon.

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	[1]	$ 173,729	$ 213,584
Marketable debt securities		436,296	363,625
Accounts receivable, net		121,801	73,390
Inventory		45,007	33,969
Prepaid expenses and other assets		40,290	47,616
Total current assets		817,123	732,184
Property, plant, and equipment, net		265,929	290,566
Marketable debt securities		135,004	199,901
Intangible assets, net		178,314	166,271
Goodwill		44,406	44,406
Other assets		62,680	57,685
Total assets		1,503,456	1,491,013
Current liabilities:
Accounts payable		38,756	42,114
Accrued liabilities		240,973	196,486
Lease liabilities		10,297	12,595
Liabilities for sales of future royalties		49,847	29,242
Other liabilities		4,280	0
Total current liabilities		344,153	280,437
Lease liabilities		30,042	30,574
Deferred tax liabilities		30,058	30,058
Liabilities for sales of future royalties		819,824	862,325
Other liabilities		17,082	12,205
Total liabilities		1,241,159	1,215,599
Commitments and contingencies (Notes 6)
Noncontrolling interest		7,000	0
Stockholders’ equity:
Preferred stock, par value of $0.001 per share - 25,000,000 shares authorized; nil outstanding in 2024 and in 2023		0	0
Common stock, par value of $0.001 per share - 250,000,000 shares authorized;outstanding - 92,484,330 in 2024 and 82,315,590 in 2023		92	82
Treasury stock, at cost, 69,757 in 2024 and 9,559 in 2023		(3,593)	(432)
Deferred compensation obligation		3,593	432
Additional paid-in capital		4,212,692	3,662,346
Accumulated other comprehensive (loss) income		(643)	647
Accumulated deficit		(3,956,844)	(3,387,661)
Total stockholders’ equity		255,297	275,414
Total liabilities, noncontrolling interest and stockholders' equity		$ 1,503,456	$ 1,491,013
[1] The Company's Consolidated Balance Sheet as of December 31, 2024 includes $ 13.5 million in cash and cash equivalents that can be used only to settle obligations of the consolidated variable interest entity. See "Note 7. Investment in Amlogenyx Inc."

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Preferred stock, par value		$ 0.001	$ 0.001
Preferred stock, shares authorized		25,000,000	25,000,000
Preferred stock, shares outstanding		0	0
Common stock, par value		$ 0.001	$ 0.001
Common stock, shares authorized		250,000,000	250,000,000
Common stock, shares outstanding		92,484,330	82,315,590
Treasury stock , shares		69,757	9,559
Cash and cash equivalents	[1]	$ 173,729	$ 213,584
Amlogenyx Inc [Member]
Cash and cash equivalents		$ 13,500
[1] The Company's Consolidated Balance Sheet as of December 31, 2024 includes $ 13.5 million in cash and cash equivalents that can be used only to settle obligations of the consolidated variable interest entity. See "Note 7. Investment in Amlogenyx Inc."

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues:
Total revenues	$ 560,230	$ 434,249	$ 363,329
Operating expenses:
Cost of sales	76,728	45,209	28,320
Research and development	697,865	648,449	705,789
Selling, general and administrative	321,610	309,799	278,139
Total operating expenses	1,096,203	1,003,457	1,012,248
Loss from operations	(535,973)	(569,208)	(648,919)
Interest income	36,506	26,688	11,074
Change in fair value of equity investments	(1,115)	397	(19,299)
Non-cash interest expense on liabilities for sales of future royalties	(63,041)	(66,004)	(43,015)
Other expense	(3,963)	(337)	(1,566)
Loss before income taxes	(567,586)	(608,464)	(701,725)
(Provision for) benefit from income taxes	(1,597)	1,825	(5,696)
Net loss	$ (569,183)	$ (606,639)	$ (707,421)
Net loss per share, basic	$ (6.29)	$ (8.25)	$ (10.12)
Net loss per share, diluted	$ (6.29)	$ (8.25)	$ (10.12)
Shares used in computing net loss per share, Basic	90,538,118	73,543,862	69,914,225
Shares used in computing net loss per share, Diluted	90,538,118	73,543,862	69,914,225
Product sales
Revenues:
Total revenues	$ 285,415	$ 180,413	$ 118,927
Royalty revenue
Revenues:
Total revenues	274,815	182,652	21,692
Collaboration and license
Revenues:
Total revenues	$ 0	$ 71,184	$ 222,710

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (569,183)	$ (606,639)	$ (707,421)
Other comprehensive income (loss):
Foreign currency translation adjustments	(1,044)	239	(724)
Changes in unrealized gain (loss) on available-for-sale securities	(246)	6,981	(4,445)
Other comprehensive income (loss):	(1,290)	7,220	(5,169)
Total comprehensive loss	$ (570,473)	$ (599,419)	$ (712,590)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Treasury Stock	Deferred Compensation Obligation
Beginning balance at Dec. 31, 2021	$ 922,561	$ 69	$ 2,997,497	$ (1,404)	$ (2,073,601)
Beginning balance, shares at Dec. 31, 2021		69,344,998
Stock-based compensation	131,710		131,710
Issuance of common stock under equity plan awards, net of tax	10,813	$ 1	10,812
Issuance of common stock under equity plan awards, net of tax, shares		852,299
Other comprehensive income (loss)	(5,169)			(5,169)
Net loss	(707,421)				(707,421)
Ending balance at Dec. 31, 2022	352,494	$ 70	3,140,019	(6,573)	(2,781,022)
Ending balance, shares at Dec. 31, 2022		70,197,297
Issuance of common stock and pre-funded warrants in connection with underwritten public offering, net of issuance costs	326,456	$ 10	326,446
Issuance of common stock and pre-funded warrants in connection with underwritten public offering, net of issuance costs,shares		9,833,334
Issuance of common stock in connection with at-the-market offering, net of issuance costs	$ 53,299	$ 1	53,298
Issuance of common stock in connection with at-the-market offering, net of issuance costs, shares	1,175,584	1,175,584
Stock-based compensation	$ 134,169		134,169
Issuance of common stock upon exercise of warrants and under equity plan awards, net of tax	8,415	$ 1	8,414
Issuance of common stock upon exercise of warrants and under equity plan awards, net of tax, shares		1,109,375
Deferred compensation						$ (432)	$ 432
Other comprehensive income (loss)	7,220			7,220
Net loss	(606,639)				(606,639)
Ending balance at Dec. 31, 2023	$ 275,414	$ 82	3,662,346	647	(3,387,661)	(432)	432
Ending balance, shares at Dec. 31, 2023	82,315,590	82,315,590
Issuance of common stock and pre-funded warrants in connection with underwritten public offering, net of issuance costs	$ 380,983	$ 9	380,974
Issuance of common stock and pre-funded warrants in connection with underwritten public offering, net of issuance costs,shares		8,782,051
Stock-based compensation	158,115		158,115
Issuance of common stock under equity plan awards, net of tax	11,258	$ 1	11,257
Issuance of common stock under equity plan awards, net of tax, shares		1,386,689
Deferred compensation						(3,161)	3,161
Other comprehensive income (loss)	(1,290)			(1,290)
Net loss	(569,183)				(569,183)
Ending balance at Dec. 31, 2024	$ 255,297	$ 92	$ 4,212,692	$ (643)	$ (3,956,844)	$ (3,593)	$ 3,593
Ending balance, shares at Dec. 31, 2024	92,484,330	92,484,330

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net loss	$ (569,183)	$ (606,639)	$ (707,421)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	158,030	135,227	130,377
Acquired in-process research and development	0	0	75,033
Amortization of premium (discount) on marketable debt securities, net	(12,624)	(12,842)	2,699
Depreciation and amortization	35,543	26,006	18,220
Change in fair value of equity investments	1,115	(397)	19,299
Non-cash collaboration royalty revenue	(100,539)	(69,364)	(21,692)
Non-cash interest expense on liabilities for sales of future royalties	63,041	66,004	43,015
Other	(3,489)	2,300	(230)
Changes in operating assets and liabilities:
Accounts receivable	(33,598)	(22,778)	(12,068)
Inventory	(11,207)	(6,930)	(9,701)
Prepaid expenses and other assets	11,731	15,325	3,798
Accounts payable, accrued, and other liabilities	46,992	901	79,845
Deferred tax liabilities	0	(1,619)	(1,639)
Net cash used in operating activities	(414,188)	(474,806)	(380,465)
Investing activities:
Purchase of property, plant, and equipment	(7,491)	(44,267)	(116,123)
Acquisition, net of cash acquired	0	0	(75,025)
Purchase of marketable debt securities	(408,613)	(526,382)	(614,735)
Proceeds from sale of marketable debt securities	3,247	50,672	84,275
Proceeds from sale of equity investments	0	0	10,094
Proceeds from maturities of marketable debt securities	410,025	695,525	450,706
Payment for intangible asset	(12,500)	(2,500)	(30,000)
Other	(2,436)	(5,048)	(844)
Net cash (used in) provided by investing activities	(17,768)	168,000	(291,652)
Financing activities:
Proceeds from the sale of future royalties, net	0	0	490,950
Proceeds from the issuance of common stock and pre-funded warrants in connection with underwritten public offerings, net of issuance costs	380,983	326,456	0
Proceeds from the issuance of common stock in connection with at-the-market offering, net of issuances costs	0	53,299	0
Proceeds from the issuance of common stock from exercise of equity plan awards, net	11,258	8,415	10,813
Proceeds from issuance of equity interest in noncontrolling interest	7,000	0	0
Other	0	(28)	(555)
Net cash provided by financing activities	399,241	388,142	501,208
Effect of exchange rate changes on cash	(2,525)	462	(1,075)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(35,240)	81,798	(171,984)
Cash, cash equivalents, and restricted cash at beginning of year	219,399	137,601	309,585
Cash, cash equivalents, and restricted cash at end of year	184,159	219,399	137,601
Supplemental disclosures of non-cash investing and financing information:
Acquired lease liabilities arising from obtaining right-of-use assets and property, plant, and equipment	9,609	22,162	1,168
Costs of property, plant and equipment included in accounts payable, accrued, and other liabilities	693	1,577	17,963
Non-cash interest expense on liabilities for sales of future royalties capitalized during the year into ending property, plant and equipment	$ 0	$ 9,431	$ 11,380

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (569,183)	$ (606,639)	$ (707,421)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	I tem 9B. Other Information During the three months ended December 31, 2024, the following directors and officers adopted a Rule 10b5-1 trading arrangement intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). Name and Title Date Adopted Aggregate Number of Shares of Common Stock to be Sold (Subject to Certain Conditions) Plan End Date Shehnaaz Suliman , M.D., Ph.D. Board Member November 8, 2024 Up to 27,110 shares, all of which are shares to be acquired upon the exercise of stock options November 7, 2025 Corsee Sanders , Ph.D., Board Member November 15, 2024 Up to 2,405 shares June 26, 2025 Matthew Fust , Board Member November 22, 2024 Up to 15,000 shares, all of which are shares to be acquired upon the exercise of stock options November 21, 2025 Eric Crombez , M.D. EVP, Chief Medical Officer December 3, 2024 Up to 64,235 shares, 28,500 of which are shares to be acquired upon the exercise of stock options December 3, 2025 Howard Horn , EVP, Chief Financial Officer December 9, 2024 Up to 17,477 shares December 9, 2025
Shehnaaz Suliman [Member]
Trading Arrangements, by Individual
Name	Shehnaaz Suliman
Title	Board Member
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	November 8, 2024
Arrangement Duration	365 days
Aggregate Available	27,110
Corsee Sanders [Member]
Trading Arrangements, by Individual
Name	Corsee Sanders
Title	Board Member
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	November 15, 2024
Arrangement Duration	224 days
Aggregate Available	2,405
Matthew Fust [Member]
Trading Arrangements, by Individual
Name	Matthew Fust
Title	Board Member
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	November 22, 2024
Arrangement Duration	365 days
Aggregate Available	15,000
Eric Crombez [Member]
Trading Arrangements, by Individual
Name	Eric Crombez
Title	Chief Medical Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 3, 2024
Arrangement Duration	366 days
Aggregate Available	64,235
Howard Horn [Member]
Trading Arrangements, by Individual
Name	Howard Horn
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 9, 2024
Arrangement Duration	366 days
Aggregate Available	17,477

Cybersecurity Risk Management,

Cybersecurity Risk Management, Strategy and Governance	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Item 1C. Cybersecurity In the ordinary course of our business, we collect, use, store, and transmit digitally large amounts of confidential, financial, sensitive, propr ietary, personal, and health-related information. The secure maintenance of this information and our information technology systems is important to our operations and business strategy. To this end, we have implemented processes designed to assess, identify, and manage risks from potential unauthorized occurrences on or through our information technology systems that may result in adverse effects on the confidentiality, integrity, and availability of these systems and the data residing therein. Our cybersecurity program is informed in part by industry standards and best practices, such as the National Institute of Standards and Technology (NIST) Cybersecurity Framework. This program is managed and monitored by a dedicated information technology team, including a Senior Director of Information Security, and is led by our Senior Vice President, Chief Information Officer, or CIO. Our processes include mechanisms, controls, technologies, and systems designed to prevent or mitigate data loss, theft, misuse, or other security incidents or vulnerabilities affecting the data and maintain a stable information technology environment. Our program includes, for example: • Regular penetration and vulnerability testing, data recovery testing, security audits, and ongoing risk assessments; • Engagement of external service providers, where appropriate, to assess, test or otherwise assist with aspects of our security controls as part of our operational security model; • Cybersecurity awareness training for our employees, contactors, incident response personnel, and senior management; • A cybersecurity incident response plan that includes procedures for responding to cybersecurity incidents and annual tabletop exercises with participants from cross functional teams; • A third-party risk management process for service providers, suppliers, and vendors including due diligence prior to engagement and ongoing periodic review of our key technology vendors, and other contractors and suppliers. Our CIO, together with our Senior Director of Information Security and other members of the IT leadership team, are responsible for assessing and managing cybersecurity risks. Our CIO has over ten years of experience managing information technology and cybersecurity. Our Senior Director of Information Security has over 25 years of experience managing information technology and cybersecurity matters and is certified as a Certified Information Systems Security Professional (CISSP). We consider cybersecurity, along with other significant risks that we face, within our overall enterprise risk management framework. Since the beginning of the last fiscal year, we have not identified any risks from known cybersecurity threats, including as a result of any prior cybersecurity incidents, that have materially affected us , but we face certain ongoing cybersecurity risks or threats that, if realized, are reasonably likely to materially affect us. Additional information on cybersecurity risks we face is discussed in Part I, Item 1A, “Risk Factors,” under the heading “Our business and operations may be materially adversely affected in the event of computer system failures or security breaches.” The Board of Directors, as a whole and at the committee level, has oversight for the most significant risks facing us and for our processes to identify, prioritize, assess, manage, and mitigate those risks. The Audit Committee, which is comprised solely of independent directors, has been designated by our Board to oversee cybersecurity risks. The Audit Committee receives regular updates on cybersecurity and information technology matters and related risk exposures from our CIO. The Board also receives updates from the Audit Committee on cybersecurity risks on a regular basis.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	The Board of Directors, as a whole and at the committee level, has oversight for the most significant risks facing us and for our processes to identify, prioritize, assess, manage, and mitigate those risks. The Audit Committee, which is comprised solely of independent directors, has been designated by our Board to oversee cybersecurity risks. The Audit Committee receives regular updates on cybersecurity and information technology matters and related risk exposures from our CIO. The Board also receives updates from the Audit Committee on cybersecurity risks on a regular basis.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Board of Directors, as a whole and at the committee level, has oversight for the most significant risks facing us and for our processes to identify, prioritize, assess, manage, and mitigate those risks. The Audit Committee, which is comprised solely of independent directors, has been designated by our Board to oversee cybersecurity risks.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee receives regular updates on cybersecurity and information technology matters and related risk exposures from our CIO. The Board also receives updates from the Audit Committee on cybersecurity risks on a regular basis.
Cybersecurity Risk Role of Management [Text Block]	Our CIO, together with our Senior Director of Information Security and other members of the IT leadership team, are responsible for assessing and managing cybersecurity risks. Our CIO has over ten years of experience managing information technology and cybersecurity. Our Senior Director of Information Security has over 25 years of experience managing information technology and cybersecurity matters and is certified as a Certified Information Systems Security Professional (CISSP). We consider cybersecurity, along with other significant risks that we face, within our overall enterprise risk management framework.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	This program is managed and monitored by a dedicated information technology team, including a Senior Director of Information Security, and is led by our Senior Vice President, Chief Information Officer, or CIO.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our CIO has over ten years of experience managing information technology and cybersecurity. Our Senior Director of Information Security has over 25 years of experience managing information technology and cybersecurity matters and is certified as a Certified Information Systems Security Professional (CISSP).

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organizat ion and Basis of Presentation Ultragenyx Pharmaceutical Inc., or the Company, is a biopharmaceutical company incorporated in Delaware. The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultrarare genetic diseases. The Company operates as one reportable segment and has four commercially approved products. Crysvita® (burosumab) is approved in the United States, or U.S., the European Union, or EU, and certain other regions for the treatment of X-linked hypophosphatemia, or XLH, in adult and pediatric patients one year of age and older. Crysvita is also approved in the U.S. and certain other regions for the treatment of fibroblast growth factor 23, or FGF23-related hypophosphatemia in tumor-induced osteomalacia, or TIO, associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adults and pediatric patients 2 years of age and older. Mepsevii® (vestronidase alfa) is approved in the U.S., the EU and certain other regions, as the first medicine for the treatment of children and adults with mucopolysaccharidosis VII, or MPS VII, also known as Sly syndrome. Dojolvi® (triheptanoin) is approved in the U.S. and certain other regions for the treatment of pediatric and adult patients severely affected by long-chain fatty acid oxidation disorders, or LC-FAOD. Evkeeza® (evinacumab) is approved in the U.S. and the European Economic Area, or EEA, and Japan for the treatment of homozygous familial hypercholesterolemia, or HoFH. The Company has exclusive rights to commercialize Evkeeza® (evinacumab) outside of the U.S. In addition to the approved products, the Company has the following ongoing clinical development programs: • UX111 (formerly ABO-102) is an AAV9 gene therapy product candidate for the treatment of patients with Sanfilippo syndrome type A, or MPS IIIA, a rare lysosomal storage disease; • DTX401 is an adeno-associated virus 8, or AAV8, gene therapy product candidate for the treatment of patients with glycogen storage disease type Ia, or GSDIa; • DTX301 is an AAV8 gene therapy product candidate in development for the treatment of patients with ornithine transcarbamylase, or OTC deficiency, the most common urea cycle disorder; • UX143 (setrusumab), which is subject to the Company ’ s collaboration agreement with Mereo BioPharma 3, or Mereo, is a fully human monoclonal antibody that inhibits sclerostin, a protein that acts on a key bone-signaling pathway and inhibits the activity of bone-forming cells for the treatment of patients with Osteogenesis Imperfecta, or OI; • GTX-102 is an antisense oligonucleotide, or ASO for the treatment of Angelman syndrome, a debilitating and rare neurogenetic disorder caused by loss-of-function of the maternally inherited allele of the UBE3A gene; and • UX701 is an adeno-associated virus 9, or AAV9, gene therapy designed to deliver stable expression of a truncated version of the ATP7B copper transporter following a single intravenous infusion to improve copper distribution and excretion from the body and reverse pathological findings of Wilson liver disease. The Company has sustained operating losses and expects such annual losses to continue in the near term. The Company’s ultimate success depends on the outcome of its research and development and commercialization activities. Through December 31, 2024 , the Company has relied primarily on its sale of equity securities, its revenues from commercial products, its sale of future royalties, and strategic collaboration arrangements to finance its operations. The Company may need to raise additional capital to fully implement its business plans through the issuance of equity, borrowings, or strategic alliances with partner companies. However, if such financing is not available at adequate levels, the Company would need to reevaluate its operating plans.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Consolidation The Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. The Company consolidates any variable interest entity, or VIE, for which it is the primary beneficiary. Segment Reporting The Company operates as one reportable segment relating to the research, development and commercialization of its products. The segment derives its current revenues from its four commercially approved products. The Company’s Chief Operating Decision Maker, or CODM, its Chief Executive Officer and the executive leadership team, manage the Company’s operations on an integrated basis for the purposes of allocating resources. When evaluating the Company’s financial performance, the CODM regularly reviews total revenues and total expenses and makes decisions using this information on a global basis. Use of Estimates The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP. The preparation of the Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the Consolidated Financial Statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, income taxes, stock-based compensation, revenue recognition, and the liabilities for sales of future royalties. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts. Restricted cash primarily consists of money market accounts used as collateral for the Company’s obligations under its facility leases and to guarantee the fulfillment of certain sales orders to certain government-sponsored customers. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows (in thousands): December 31, 2024 2023 2022 Cash and cash equivalents $ 173,729 $ 213,584 $ 132,944 Restricted cash included in other current assets 6,806 2,008 862 Restricted cash included in other non-current assets 3,624 3,807 3,795 Total cash, cash equivalents, and restricted cash $ 184,159 $ 219,399 $ 137,601 Marketable Debt Securities All marketable debt securities have been classified as “available-for-sale” and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and reevaluates such designation as of each balance sheet date. Investments with a maturity of one year or less from the balance sheet date are reported as current marketable debt securities and investments with a maturity of greater than one year from the balance sheet date are reported as non-current marketable debt securities. Unrealized gains and losses are excluded from earnings and are reported as a component of comprehensive loss. Realized gains and losses and declines in fair value judged to be other than temporary, if any, on available-for-sale securities are included in other expense. The cost of securities sold is based on the specific-identification method. Interest on investments is included in interest income. Equity Investments The Company records investments in equity securities, other than equity method investments, at fair market value, using market quotes when readily determinable. Equity securities with no readily determinable fair values are recorded using the measurement alternative of cost adjusted for observable price changes in orderly transactions for identical or similar investments of the same issuer less impairment, if any. Investments in equity securities are recorded in other assets on the Company's Consolidated Balance Sheets. Unrealized gains and losses are reported in change in fair value of equity investments on the Company’s Consolidated Statements of Operations. The Company regularly reviews its non-marketable equity securities for indicators of impairment. Concentration of Credit Risk, Credit Losses, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents, and investments. The Company’s cash, cash equivalents, and investments are held by financial institutions that management believes are of high credit quality. The Company’s investment policy limits investments to fixed income securities denominated and payable in U.S. dollars such as U.S. government obligations, money market instruments and funds, corporate bonds, commercial paper, and asset-backed securities and places restrictions on maturities and concentrations by type and issuer. Such deposits may, at times, exceed federally insured limits. The Company has not experienced any losses on its deposits of cash and cash equivalents and its accounts are monitored by management to mitigate risk. The Company is exposed to credit risk in the event of default by the financial institutions holding its cash and cash equivalents, corporate issuers, and other financial instruments, to the extent recorded in the Consolidated Balance Sheets. The Company is exposed to credit losses primarily through receivables from customers and collaborators and through its available-for-sale debt securities. For trade receivables and other financial instruments, the Company uses a forward-looking expected loss model that recognizes a current period charge for losses that are expected to be incurred over the life of the financial instrument. The Company’s expected loss allowance methodology for the receivables is developed using historical collection experience, current and future economic market conditions, a review of the current aging status and financial condition of the entities. Specific allowance amounts are established to record the appropriate allowance for customers that have a higher probability of default. Balances are written off when determined to be uncollectible. The Company’s expected loss allowance methodology for the debt securities is developed by reviewing the extent of the unrealized loss, the size, term, geographical location, and industry of the issuer, the issuers’ credit ratings and any changes in those ratings, as well as reviewing current and future economic market conditions and the issuers’ current status and financial condition. For available-for-sale debt securities with unrealized losses, the losses are recognized as allowances rather than as reductions in the amortized cost of the securities. There was no allowance for losses on available-for-sale debt securities which were attributable to credit risk for the years ended December 31, 2024 and 2023. The Company is dependent on third-party manufacturers to supply products for research and development activities in its programs. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs. Inventory The Company values inventory at the lower of cost and net realizable value and determines the cost of inventory using the average-cost method. The Company expenses costs associated with the manufacture of product candidates prior to regulatory approval. Inventories consist of currently approved products. The Company periodically reviews its inventories for excess amounts or obsolescence and writes down obsolete or otherwise unmarketable inventory to its estimated net realizable value. Management determines excess inventory based on expected future demand. Estimates related to future demand are sensitive to significant inputs and assumptions such as acceptance by patients and physicians and the availability of formulary coverage and adequate reimbursement from private third-party payers for the product. Property, Plant, and Equipment Property, plant, and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the respective assets. Depreciation and amortization begins when the asset is placed in service. Interest costs incurred during the construction of major capital projects are capitalized until the underlying asset is ready to be placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation or amortization are removed from the balance sheet and the resulting gain or loss, if any, is reflected in operations. See “Note 4. Balance Sheet Components” for further disclosure on the useful lives of property, plant, and equipment. Intangible Assets Finite-lived intangibles consist of contractual payments made for certain milestones achieved with collaboration partners. The contractual payments are recorded as intangible assets and are amortized over their estimated useful lives. The Company reviews its definite-lived intangible assets when events or circumstances may indicate that the carrying value of these assets is not recoverable and exceeds their fair value. The Company measures fair value based on the estimated future undiscounted cash flows associated with these assets in addition to other assumptions and projections that the Company deems to be reasonable and supportable. Indefinite-lived intangibles consist of acquired in-process research and development, or IPR&D. IPR&D assets represent capitalized incomplete research projects that the Company acquired through business combinations. Such assets are initially measured at their acquisition date fair values and are tested for impairment annually and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. When development of the project is complete, which generally occurs when regulatory approval to market a product is obtained, the associated assets will be deemed finite-lived and will be amortized over a period that best reflects the economic benefits provided by these assets. If it is determined that an intangible asset becomes impaired, the carrying value is written down to its fair value with the related impairment charge recognized in Consolidated Statements of Operations in the period in which the impairment occurs. The Company has not recorded any impairments of intangible assets to date. Goodwill Goodwill represents the excess of purchase price over fair value of net assets acquired in a business combination and is not amortized. Goodwill is subject to impairment testing at least annually during the fourth quarter or when a triggering event occurs that could indicate a potential impairment. If it is determined that the goodwill becomes impaired, the carrying value is written down to its fair value with the related impairment charge recognized in Consolidated Statements of Operations in the period in which the impairment occurs. The Company has not recorded any impairments of goodwill. Impairment of Long-Lived Assets The Company evaluates its long-lived assets, including property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of each asset to the future undiscounted cash flows expected to result from the use of the asset and its eventual disposition. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. The Company has not recorded material impairment of any long-lived assets. Accruals of Research and Development Costs The Company records accruals for estimated costs of research, preclinical and clinical studies and manufacturing development. These costs are a significant component of the Company’s research and development expenses. A substantial portion of the Company’s ongoing research and development activities are conducted by third-party service providers, including contract research organizations. The Company accrues the costs incurred under its agreements with these third parties based on actual work completed in accordance with agreements established with these third parties. The Company determines the actual costs through obtaining information from external service providers as to the progress or stage of completion of the services and the agreed-upon fee to be paid for such services. Liabilities for Sales of Future Royalties The Company sold the right to receive certain royalty payments from net sales of Crysvita in certain territories to RPI Finance Trust, or RPI, an affiliate of Royalty Pharma, and to OCM LS23 Holdings LP, an investment vehicle for Ontario Municipal Employees Retirement System, or OMERS, as further described in “Note 11. Liabilities for Sales of Future Royalties.” The Company recorded the liabilities at inception based upon estimated future cash flows discounted at a market rate. The liabilities are being amortized using the effective interest method over the estimated life of the applicable arrangement. In order to determine the amortization of the liabilities, the Company is required to estimate the total amount of future royalty payments to be received by the Company and paid to RPI and OMERS, subject to the capped amount, over the life of the arrangements. The excess of future estimated royalty payments (subject to the capped amount) to RPI and OMERS is recorded as non-cash interest expense over the life of the arrangements. Consequently, the Company estimates an imputed interest on the unamortized portion of the liabilities and records interest expense relating to the transactions. The Company periodically assesses the expected royalty payments using a combination of historical results, internal projections and forecasts from external sources. To the extent such payments are greater or less than the Company’s initial estimates or the timing of such payments is materially different than its original estimates, the Company employs the prospective method to adjust the amortization of the liabilities and the effective interest rate. Revenue Recognition Product Sales The Company sells its approved products through a limited number of distributors. Under Accounting Standards Codification, or ASC, 606, Revenue from Contracts with Customers, revenue from product sales is recognized at the point in time when control is transferred to these distributors. The Company also recognizes revenue from sales of certain products on a “named patient” basis, which are allowed in certain countries prior to the commercial approval of the product. Prior to recognizing revenue, the Company makes estimates of the transaction price, including any variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Product sales are recorded net of estimated government-mandated rebates and chargebacks, estimated product returns, and other deductions. Provisions for returns and other adjustments are provided for in the period the related revenue is recorded, as estimated by management. These reserves are based on estimates of the amounts earned or to be claimed on the related sales and are reviewed periodically and adjusted as necessary. The Company’s estimates of government mandated rebates, chargebacks, estimated product returns, and other deductions depends on the identification of key customer contract terms and conditions, as well as estimates of sales volumes to different classes of payors. If actual results vary, the Company may need to adjust these estimates, which could have a material effect on earnings in the period of the adjustment. Collaboration, License, and Royalty Revenue The Company has certain license and collaboration agreements that are within the scope of ASC 808, Collaborative Agreements , which provides guidance on the presentation and disclosure of collaborative arrangements. Generally, the classification of the transactions under the collaborative arrangements is determined based on the nature of contractual terms of the arrangement, along with the nature of the operations of the participants. The Company records its share of collaboration revenue, net of transfer pricing related to net sales in the period in which such sales occur, if the Company is considered as an agent in the arrangement. The Company is considered an agent when the collaboration partner controls the product before transfer to the customers and has the ability to direct the use of and obtain substantially all of the remaining benefits from the product. Funding received related to research and development services and commercialization costs is generally classified as a reduction of research and development expenses and selling, general and administrative expenses, respectively, in the Consolidated Statements of Operations, because the provision of such services for collaborative partners are not considered to be part of the Company’s ongoing major or central operations. The Company utilizes certain information from its collaboration partners to record collaboration revenue, including revenue from the sale of the product, associated reserves on revenue, and costs incurred for development and sales activities. For the periods covered in the financial statements presented, there have been no material changes to prior period estimates of revenues and expenses. The Company also records royalty revenues under certain of the Company’s license or collaboration agreements in exchange for license of intellectual property. As described in “Note 11. Liabilities for Sales of Future Royalties”, for certain royalty payments from net sales of Crysvita in applicable territories that were sold to RPI and OMERS, the Company records the royalty revenue on a prospective basis as non-cash royalty revenue in the Consolidated Statements of Operations over the term of the applicable arrangement. The terms of the Company’s collaboration and license agreements may contain multiple performance obligations, which may include licenses and research and development activities. The Company evaluates these agreements under ASC 606, Revenue from Contracts with Customers , to determine the distinct performance obligations. The Company analogizes to ASC 606 for the accounting for distinct performance obligations for which there is a customer relationship. Prior to recognizing revenue, the Company makes estimates of the transaction price, including variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Total consideration may include nonrefundable upfront license fees, payments for research and development activities, reimbursement of certain third-party costs, payments based upon the achievement of specified milestones, and royalty payments based on product sales derived from the collaboration. If there are multiple distinct performance obligations, the Company allocates the transaction price to each distinct performance obligation based on its relative standalone selling price. The standalone selling price is generally determined based on the prices charged to customers or using expected cost-plus margin. The Company estimates the efforts needed to complete the performance obligations and recognizes revenue by measuring the progress towards complete satisfaction of the performance obligations using input measures. Deferred Compensation Plan The Company maintains a nonqualified deferred compensation plan whereby certain employees and members of the board of directors are able to defer certain equity awards and other compensation. Amounts deferred are invested into shares of the Company's common stock and corporate-owned life insurance. The plan complies with the provisions of Section 409A of the Internal Revenue Code. All the investments held in the plan are recorded in other non-current assets in the Consolidated Balance Sheets. The short-term portion of the corresponding liability for the plan is included in accrued expenses. The long-term portion of the liability is included in other non-current liabilities in the Consolidated Balance Sheets. Changes in the value of the deferred compensation assets and liabilities are recorded in earnings as they occur. Certain equity awards deferred under the plan are required to be settled through the issuance of Company stock. These awards are recorded as treasury stock and deferred compensation obligation within stockholders’ equity. Leases Lease agreements are evaluated to determine whether an arrangement is or contains a lease in accordance with ASC 842, Leases . The Company determines if an arrangement includes a lease at inception. Right-of-use lease assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date. The right-of-use lease asset includes any lease payments made and excludes lease incentives. Incremental borrowing rate is used in determining the present value of future payments. The Company applies a portfolio approach to the property leases to apply an incremental borrowing rate to leases with similar lease terms. The lease terms may include options to extend or terminate the lease. The Company recognizes the options to extend the lease as part of the right-of-use lease assets and lease liabilities only if it is reasonably certain that the option would be exercised. Lease expense for minimum lease payments is recognized on a straight-line basis over the non-cancelable lease term. The Company has elected to not separate lease and non-lease components. See “Note 10. Leases” for further disclosure. Comprehensive Loss Comprehensive loss is the change in stockholders’ equity from transactions and other events and circumstances other than those resulting from investments by stockholders and distributions to stockholders. The Company’s other comprehensive loss is comprised of unrealized gains and losses on investments in available-for-sale securities and foreign currency translation adjustments. Research and Development Research and development costs are expensed as incurred and consist of salaries and benefits, stock-based compensation expense, lab supplies and facility costs, as well as fees paid to other nonemployees and entities that conduct certain research and development activities on the Company’s behalf. Amounts incurred in connection with license agreements are also included in research and development expense. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred. The deferred amounts are expensed as the related goods are delivered or the services are performed. Stock-Based Compensation Stock-based awards issued to employees, including stock options, performance stock options, or PSOs, restricted stock units, or RSUs, and performance stock units, or PSUs are recorded at fair value as of the grant date and recognized as expense on a straight-line basis over the employee’s requisite service period (generally the vesting period). PSOs and PSUs vest only if certain specified criteria are achieved and the employees’ continued service requirements are met; therefore, the expense recognition occurs when the likelihood of the PSOs and PSUs being earned is deemed probable. Stock compensation expense on awards expected to vest is recognized net of estimated forfeitures. Income Taxes The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and the tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company must then assess the likelihood that the resulting deferred tax assets will be realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. Due to the Company’s lack of earnings history, the net deferred tax assets have been fully offset by a valuation allowance. In conjunction with the acquisition of Dimension Therapeutics, Inc., or Dimension, a deferred tax liability was recorded reflecting the tax impact of the difference between the book basis and tax basis of acquired IPR&D. Such deferred income tax liability is not used to offset deferred tax assets when analyzing the Company’s valuation allowance as the acquired IPR&D is considered to have an indefinite life until the Company completes or abandons development of the acquired IPR&D. The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon examination based solely on their technical merits, as the largest amount of benefit that is more likely than not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits. Foreign Currency Assets and liabilities of non-U.S. subsidiaries that operate in a local currency environment, where the local currency is the functional currency, are translated to U.S. dollars at exchange rates in effect at the balance sheet date, with the resulting translation adjustments directly recorded to a separate component of accumulated other comprehensive loss. Income and expense accounts are translated at average exchange rates for the period. Transactions which are not in the functional currency of the entity are remeasured into the functional currency and gains or losses resulting from the remeasurement recorded in other expense. Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for common stock equivalents. Shares of common stock into which pre-funded warrants may be exercised are considered outstanding for the purposes of computing basic net loss per share because the shares may be issued for little or no consideration, are fully vested and are exercisable after the original issuance date. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are antidilutive. In periods when we have incurred a net loss, options and warrants to purchase common stock are considered common stock equivalents, but have been excluded from the calculation of diluted net loss per share, as their effect is antidilutive. Recent Accounting Pronouncements In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses , requiring public entities to disclose additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the impact of adopting ASU 2024-03. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures , requiring public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. The Company adopted ASU 2023-07 during the year ended December 31, 2024.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Certain financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. The carrying amounts of liabilities for the sales of future royalties also approximate their fair value. Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 —Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2 —Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and Level 3 —Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data. The Company’s financial instruments consist of Level 1, Level 2, and Level 3 assets. Where quoted prices are available in an active market, securities are classified as Level 1. Money market funds and U.S. Government treasury bills are classified as Level 1. Level 2 assets consist primarily of corporate bonds, asset backed securities, commercial paper, U.S. Government Treasury and agency securities, and debt securities in government-sponsored entities based upon quoted market prices for similar movements in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. Where applicable these models project future cash flows and discount the future amounts to a present value using market-based observable inputs obtained from various third-party data providers, including but not limited to, benchmark yields, interest rate curves, reported trades, broker/dealer quotes and reference data. The Company determines the fair value of its equity investment in Solid Biosciences, Inc., or Solid, by using the quoted market prices, which are Level 1 fair value measurements. The following tables set forth the fair value of the Company’s financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy (in thousands): December 31, 2024 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 113,894 $ — $ — $ 113,894 Time deposits — 10,000 — 10,000 Corporate bonds — 391,731 — 391,731 Commercial paper — 21,194 — 21,194 Asset-backed securities — 143 — 143 U.S. Government Treasury and agency securities — 158,814 — 158,814 Investment in Solid common stock 2,089 — — 2,089 Deferred compensation assets — 15,337 — 15,337 Total financial assets $ 115,983 $ 597,219 $ — $ 713,202 Financial Liabilities: Deferred compensation liabilities $ — $ 15,756 $ — $ 15,756 December 31, 2023 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 162,289 $ — $ — $ 162,289 Certificates of deposit and time deposits — 17,986 — 17,986 Corporate bonds — 215,166 — 215,166 Commercial paper — 20,620 — 20,620 Asset-backed securities — 2,712 — 2,712 U.S. Government Treasury and agency securities 57,437 259,605 — 317,042 Investment in Solid common stock 3,204 — — 3,204 Deferred compensation assets — 10,220 — 10,220 Total financial assets $ 222,930 $ 526,309 $ — $ 749,239 Financial Liabilities: Deferred compensation liabilities $ — $ 10,365 $ — $ 10,365 Deferred compensation liabilities consist of short-term liabilities of $ 0.6 million and $ 0.2 million as of December 31, 2024 and 2023 , respectively, included in accrued liabilities on the Consolidated Balance Sheets, and long-term liabilities of $ 15.2 million and $ 10.1 million as of December 31, 2024 and 2023, respectively, included in other non-current liabilities on the Consolidated Balance Sheets. There have been no significant net gains or losses on deferred compensation assets or liabilities for the periods presented.

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Balance Sheet Components	4. Balance Sheet Components Cash Equivalents and Marketable Debt Securities The fair values of cash equivalents and marketable debt securities classified as available-for-sale securities consisted of the following (in thousands): December 31, 2024 Amortized Gross Unrealized Estimated Cost Gains Losses Fair Value Money market funds $ 113,894 $ — $ — $ 113,894 Time deposits 10,000 — — 10,000 Corporate bonds 391,124 809 ( 202 ) 391,731 Commercial paper 21,194 — — 21,194 Asset-backed securities 143 — — 143 U.S. Government Treasury and agency securities 158,414 404 ( 4 ) 158,814 Total $ 694,769 $ 1,213 $ ( 206 ) $ 695,776 December 31, 2023 Amortized Gross Unrealized Estimated Cost Gains Losses Fair Value Money market funds $ 162,289 $ — $ — $ 162,289 Certificates of deposit and time deposits 17,986 — — 17,986 Corporate bonds 214,792 711 ( 337 ) 215,166 Commercial paper 20,620 — — 20,620 Asset-backed securities 2,715 — ( 3 ) 2,712 U.S. Government Treasury and agency securities 316,160 982 ( 100 ) 317,042 Total $ 734,562 $ 1,693 $ ( 440 ) $ 735,815 At December 31, 2024 , the remaining contractual maturities of available-for-sale securities were less than three years . There have been no significant realized gains or losses on available-for-sale securities for the periods presented. All marketable securities with unrealized losses at December 31, 2024 have been in a loss position for less than 12 months or the loss is not material and is temporary in nature. Inventory Inventory consists of the following (in thousands): December 31, 2024 2023 Work-in-process $ 21,967 $ 18,859 Finished goods 23,040 15,110 Total inventory $ 45,007 $ 33,969 Property, Plant, and Equipment, net Property, plant, and equipment, net consists of the following (in thousands): December 31, Useful life (years) 2024 2023 Building 20 - 30 $ 181,576 $ 181,356 Leasehold improvements Shorter of lease term or estimated useful life 58,021 58,683 Research and development equipment 5 60,233 56,347 Furniture and office equipment 5 6,475 6,419 Computer equipment and software 3 - 5 16,365 16,196 Manufacturing equipment 5 - 15 37,332 37,297 Land Not applicable 16,619 16,619 Other Varies by asset 1,790 1,050 Property, plant, and equipment, gross 378,411 373,967 Less: accumulated depreciation ( 112,482 ) ( 83,401 ) Property, plant, and equipment, net $ 265,929 $ 290,566 Depreciation expense for the years ended December 31, 2024, 2023, and 2022 was $ 30.1 million, $ 22.2 million and $ 15.0 million, respectively. Amortization of leasehold improvements and software is included in depreciation expense. Accrued Liabilities Accrued liabilities consists of the following (in thousands): December 31, 2024 2023 Research, clinical study, and manufacturing expenses $ 88,133 $ 65,326 Payroll and related expenses 94,021 82,936 Revenue related reserves 33,344 17,029 Other 25,475 31,195 Total accrued liabilities $ 240,973 $ 196,486

Intangible Assets, Net

Intangible Assets, Net	12 Months Ended
	Dec. 31, 2024
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets, Net	5. Intangible Assets, net Indefinite-lived Intangibles As a result of the accounting for our acquisition of Dimension Therapeutics, Inc. in November 2017, the Company has IPR&D assets of $ 129.0 million as of December 31, 2024 and 2023. IPR&D assets represent the fair value of acquired programs to develop an AAV gene therapy for OTC deficiency and to develop an AAV gene therapy for glycogen storage disease type Ia. IPR&D assets are considered to be indefinite-life until the completion or abandonment of the associated research and development efforts. Finite-lived Intangibles Subsequent to the FDA approval of Dojolvi for the treatment of LC-FAOD in 2020, the Company recorded $ 4.8 million for the attainment of various development and commercial milestones as finite-lived intangible assets which are amortized over a weighted-average total useful life of 6 years. In January 2022, the Company announced a collaboration with Regeneron to commercialize Evkeeza for HoFH outside of the U.S. Pursuant to the collaboration agreement, the Company has incurred an upfront payment and regulatory and sales milestones to date totaling $ 57.5 million. As these payments are for the Company’s use of intellectual property for Evkeeza for HoFH, they were recorded as intangible assets , which are amortized over a weighted-average total useful life of 9 years. The Company's intangible assets were as follows: December 31, 2024 Gross Carrying Amount Weighted-Average Life (Years) Accumulated Amortization Net Carrying Amount Indefinite-lived intangibles $ 129,000 — $ — $ 129,000 Finite-lived intangibles 62,275 9 ( 12,961 ) 49,314 Total intangible assets $ 191,275 — $ ( 12,961 ) $ 178,314 December 31, 2023 Gross Carrying Amount Weighted-Average Life (Years) Accumulated Amortization Net Carrying Amount Indefinite-lived intangibles $ 129,000 — $ — $ 129,000 Finite-lived intangibles 44,775 10 ( 7,504 ) 37,271 Total intangible assets $ 173,775 — $ ( 7,504 ) $ 166,271 The Company recorded costs of sales of $ 5.5 million, $ 3.8 million and $ 3.2 million for the years ended December 31, 2024, 2023, and 2022, respectively, related to the amortization of the intangible assets. The expected amortization of the intangible assets, as of December 31, 2024, for each of the next five years and thereafter is as follows: 2025 $ 7,162 2026 7,162 2027 6,722 2028 6,282 2029 6,282 Thereafter 15,704 Total $ 49,314

Revenue

Revenue	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue	6. Revenue The following table disaggregates total revenues from external customers by product sales, royalty revenue, and collaboration and license revenue (in thousands): Year Ended December 31, 2024 2023 2022 Product sales: Crysvita $ 134,709 $ 75,697 $ 42,678 Dojolvi 88,194 70,633 55,612 Evkeeza 32,162 3,642 — Mepsevii 30,350 30,441 20,637 Total product sales 285,415 180,413 118,927 Crysvita royalty revenue 274,815 182,652 21,692 Collaboration and license revenue: Crysvita collaboration revenue in Profit-Share Territory — 69,705 215,024 Other — 1,479 7,686 Total collaboration and license revenue — 71,184 222,710 Total revenues $ 560,230 $ 434,249 $ 363,329 The following table disaggregates total revenues based on geographic location (in thousands): Year Ended December 31, 2024 2023 2022 North America $ 340,463 $ 307,149 $ 281,088 Latin America 130,713 77,342 44,711 Europe, Middle East, and Africa 80,124 47,534 36,369 Asia-Pacific 8,930 2,224 1,161 Total revenues $ 560,230 $ 434,249 $ 363,329 The following table presents the activity and ending balances for product sales related accruals and allowances (in thousands): Year Ended December 31, 2024 2023 2022 Balance of product sales reserve at beginning of year $ 17,029 $ 11,487 $ 7,181 Provisions 38,102 18,761 13,525 Payments ( 21,391 ) ( 12,746 ) ( 9,613 ) Adjustments ( 434 ) ( 473 ) 394 Balance of product sales reserve at end of year $ 33,306 $ 17,029 $ 11,487 The following table presents changes in the contract liabilities for the years ended December 31, 2023 (in thousands): December 31, 2023 Balance of contract liabilities at beginning of period $ 1,479 Additions — Deductions ( 1,479 ) Balance of contract liabilities at end of period, net $ — See “Note 9. License and Research Agreements” for additional details on contract liabilities activities. The Company’s largest accounts receivable balance was from a collaboration partner, KKC, and was 70 % and 53 % of the total accounts receivable balance as of December 31, 2024 and 2023 , respectively.

Investment in Amlogenyx. Inc.

Investment in Amlogenyx. Inc.	12 Months Ended
	Dec. 31, 2024
Investments, All Other Investments [Abstract]
Investment in Amlogenyx. Inc.	7. Investment in Amlogenyx. Inc. In July 2024, the Company contributed certain intellectual property rights to Amlogenyx Inc., or Amlogenyx, a subsidiary of the Company, and received 9.0 million shares of common stock of Amlogenyx. A third-party investor along with one of its affiliated entities, and the Company, each contributed $ 7.0 million to Amlogenyx and in exchange, each received approximately 1.6 million shares of series seed preferred stock of Amlogenyx. The purpose of Amlogenyx is to pursue the application of the Company’s novel adeno-associated virus, or AAV, gene therapy to treat beta-amyloid disorders and related neurodegenerative diseases. Amlogenyx was determined to be a VIE and the Company is the primary beneficiary as it has the power to direct the activities that would most significantly impact the economic performance of Amlogenyx, including the performance of R&D activities relating to its sole product candidate. As the primary beneficiary, the Company has consolidated the financial position, results of operations and cash flows of Amlogenyx in its financial statements and all intercompany balances have been eliminated in consolidation. Upon initial consolidation, the non-controlling interest of the third-party investor was recorded at its estimated fair value of $ 7.0 million, which is equal to their original investment. As of December 31, 2024 , total assets and liabilities included on the Consolidated Balance Sheets for Amlogenyx were $ 13.5 million and $ 0.1 million, respectively. The assets primarily consisted of cash and cash equivalents which may only be used to settle obligations of Amlogenyx. Noncontrolling interest related to the third-party investment in Amlogenyx is reported on the Consolidated Balance Sheets in mezzanine equity. Changes in the carrying value of noncontrolling interest for the year ended December 31, 2024, were as follows: Noncontrolling Interest As of December 31, 2023 $ — Issuance of equity from noncontrolling interest 7,000 As of December 31, 2024 $ 7,000 In October 2024, Amlogenyx granted 778,500 stock options to its employees from its 2024 Equity Incentive Plan, which authorizes 1,358,060 shares for issuance. For the year ended December 31, 2024 , stock-based compensation related to these awards was immaterial.

GeneTx Acquisition

GeneTx Acquisition	12 Months Ended
	Dec. 31, 2024
Business Combinations [Abstract]
GeneTx Acquisition	8. GeneTx Acquisition In August 2019, the Company entered into a Program Agreement and a Unitholder Option Agreement with GeneTx Biotherapeutics LLC, or GeneTx, to collaborate on the development of GeneTx’s GTX-102, an ASO for the treatment of Angelman syndrome. In July 2022, pursuant to the terms of the Unitholder Option Agreement, as amended, the Company exercised the option to acquire GeneTx and entered into a Unit Purchase Agreement, or the Purchase Agreement, pursuant to which the Company purchased all the outstanding units of GeneTx. In accordance with the terms of the Purchase Agreement, the Company paid the option exercise price of $ 75.0 million and an additional $ 15.6 million to acquire the outstanding cash of GeneTx, and adjustments for working capital and transaction expenses of $ 0.6 million, for a total purchase consideration of $ 91.2 million. During the year ended December 31, 2024, the Company achieved a $ 30.0 million regulatory milestone upon the initiation of the Phase 3 Aspire clinical study for GTX-102. The Company is obligated to pay up to $ 85.0 million in additional regulatory approval milestones for the achievement of U.S. and EU product approvals, and up to $ 75.0 million in commercial milestone payments based on annual worldwide net product sales, contingent upon the achievement of the milestones. The Company will also pay tiered mid- to high single-digit percentage royalties based on licensed product annual net sales. If the Company receives and resells an FDA priority review voucher, or PRV, in connection with a new drug application approval, GeneTx unitholders are entitled to receive a portion of proceeds from the sale or a cash payment from the Company if the Company choses to retain the PRV. As part of the Company's acquisition of GeneTx, the Company assumed a License Agreement with Texas A&M University, or TAMU. To date, the Company recognized an aggregate of $ 0.5 million for clinical milestones under the TAMU agreement, and have in aggregate up to $ 23.0 million of future obligations for various future milestones and a nominal annual license fee that may increase up to a maximum of $ 2.0 million. The Company will also pay mid-single-digit percentage royalties based on licensed product annual net sales. As of December 31, 2024 and 2023, the Company had $ 0.5 million and nil , respectively, in collaboration payables under this arrangement. The transaction was accounted as an asset acquisition, as substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable in-process research and development intangible asset. Prior to the achievement of certain development and regulatory milestones, the acquired in-process research and development intangible asset has not yet reached technological feasibility and has no alternative future use. Accordingly, to date, amounts paid to acquire GeneTx, net of cash and working capital acquired, were classified as in-process research and development expense.

License and Research Agreements

License and Research Agreements	12 Months Ended
	Dec. 31, 2024
Research Grant Agreement [Abstract]
License and Research Agreements	9. License and Research Agreements Kyowa Kirin Co., Ltd. In August 2013, the Company entered into a collaboration and license agreement with Kyowa Kirin Co., Ltd., or KKC. Under the terms of this collaboration and license agreement, as amended, the Company and KKC collaborate on the development and commercialization of Crysvita in the field of orphan diseases in the U.S. and Canada, or the Profit-Share Territory, and in the European Union, UK, and Switzerland, or the European Territory, and the Company has the right to develop and commercialize such products in the field of orphan diseases in Mexico and Central and South America, or Latin America. The collaboration and license agreements are within the scope of ASC 808, which provides guidance on the presentation and disclosure of collaborative arrangements. Product Sales Revenue for Latin America and Turkey The Company is responsible for commercializing Crysvita in Latin America and Turkey. The Company is considered the principal in these territories as the Company controls the product before it is transferred to the customer. Accordingly, the Company records revenue on a gross basis for the sale of Crysvita once the product is delivered and the risk and title of the product is transferred to the distributor. In Turkey, KKC has the option to assume responsibility for commercialization efforts. Transfer Price and Royalties on Product Sales Revenue Under the collaboration agreement, KKC manufactures and supplies Crysvita, which is purchased by the Company for sales in Latin America and Turkey, and charges the Company a transfer price of 30 % of net sales. The transfer price on these sales was 35 % prior to December 31, 2022. The Company also pays to KKC a low single-digit royalty on net sales in Latin America. Collaboration and Royalty Revenue for Sales in the Profit-Share Territory The Company and KKC shared commercial responsibilities and profits in the Profit-Share Territory until April 2023. Under the collaboration agreement, KKC manufactured and supplied Crysvita for commercial use in the Profit-Share Territory and charged the Company a transfer price of 30 % of net sales in 2023, and 35 % prior to December 31, 2022. The remaining profit or loss after supply costs from commercializing products in the Profit-Share Territory was shared between the Company and KKC on a 50 / 50 basis until April 2023. In April 2023, commercialization responsibilities for Crysvita in the Profit-Share Territory transitioned to KKC. Thereafter, the Company is entitled to receive a tiered double-digit revenue share from the mid- 20 % range up to a maximum rate of 30 %. The parties subsequently agreed that the Company would have the right to continue to support KKC in commercial field activities in the U.S. through January 31, 2025, as amended. After January 31, 2025, the Company’s rights to promote Crysvita in the U.S. are limited to medical geneticists and the Company solely bears its expenses for the promotion of Crysvita in the Profit-Share Territory. During the prior profit-share period, as KKC was the principal in the sale transaction with the customer, the Company recognized a pro-rata share of collaboration revenue, net of transfer pricing, in the period the sale occurred. The Company concluded that its portion of KKC’s sales in the Profit-Share Territory prior to April 2023 was analogous to a royalty and therefore recorded its share as collaboration revenue, similar to a royalty. Starting in April 2023, the Company began to record as royalty revenue in the period the underlying sales occurred. In July 2022, the Company sold to OMERS its right to receive 30 % of the future royalty payments due to the Company based on net sales of Crysvita in the U.S. and Canada, subject to a cap, beginning in April 2023, as further described in “Note 11. Liabilities for Sales of Future Royalties.” Royalty Revenue for Sales in the European Territory KKC has the commercial responsibility for Crysvita in the European Territory. In December 2019, the Company sold its right to receive royalty payments based on sales in the European Territory to Royalty Pharma, effective January 1, 2020, as further described in “Note 11. Liabilities for Sales of Future Royalties.” Prior to the Company’s sale of the royalty, the Company received a royalty of up to 10 % on net sales in the European Territory, which was recognized as the underlying sales occur. Beginning in 2020, the Company records the royalty revenue as non-cash royalty revenues. The Company records this revenue as royalty revenue. Total Crysvita revenue was as follows (in thousands): Year Ended December 31, 2024 2023 2022 Product sales $ 134,709 $ 75,697 $ 42,678 Revenue in profit-share territory: Royalty revenue 174,276 113,288 — Non-cash royalty revenue 74,690 48,581 — Collaboration revenue — 69,705 215,024 Total revenue in Profit-Share Territory 248,966 231,574 215,024 Non-cash royalty revenue in European Territory 25,849 20,783 21,692 Total Crysvita revenue $ 409,524 $ 328,054 $ 279,394 Development Activities In the field of orphan diseases, except for ongoing studies being conducted by KKC, the Company was the lead party for development activities in the Profit-Share Territory and in the European Territory until the applicable transition date. The Company shared the costs for development activities in the Profit-Share Territory and the European Territory conducted pursuant to the development plan before the applicable transition date equally with KKC. In April 2023, which was the transition date for the Profit-Share Territory, KKC became the lead party and became responsible for the costs of the subsequent development activities. However, the Company will continue to equally share in the costs of the studies with KKC that commenced prior to the applicable transition date. Collaboration Cost Sharing and Payments Under the collaboration agreement, KKC and the Company share certain development and commercialization costs, and as a result, the Company was reimbursed for these costs and operating expenses were reduced. KKC also receives a transfer price and royalty on net product sales revenue which is recorded in cost of sales. These amounts were recognized in the Company’s Statements of Operations in connection with the collaboration agreement with KKC as follows (in thousands): Year Ended December 31, 2024 2023 2022 Research and development $ ( 3,670 ) $ ( 6,510 ) $ ( 15,974 ) Selling, general and administrative $ ( 4,082 ) $ ( 17,199 ) $ ( 37,217 ) Cost of sales $ 46,027 $ 18,476 $ 13,250 Collaboration Receivable and Payable The Company had accounts receivable from KKC in the amount of $ 85.4 million and $ 39.2 million from profit-share revenue and royalties and other receivables recorded in other current assets of $ 1.8 million and $ 1.1 million and accrued liabilities of $ 7.1 million and $ 5.3 million from amounts owed for transfer price and royalties as well as commercial and development activity reimbursements, as of December 31, 2024 and 2023, respectively. Baylor Research Institute In September 2012, the Company entered into a license agreement with Baylor Research Institute, or BRI. Under the terms of this license agreement, as amended, BRI exclusively licensed to the Company its territories for certain intellectual property related to Dojolvi for the treatment of LC-FAOD. During the year ended December 31, 2022, the Company recorded $ 2.5 million for the attainment of a commercial milestone as a finite-lived intangible asset. The Company is obligated to make additional future payments of up to $ 7.5 million contingent upon attainment of various development and commercial milestones. Additionally, the Company pays BRI a mid- single-digit royalty on net sales of the licensed product in the licensed territories. Regeneron In January 2022, the Company announced a collaboration with Regeneron to commercialize Evkeeza for HoFH outside of the U.S. Pursuant to the terms of the agreement, the Company received the rights to develop, commercialize and distribute the product for HoFH in countries outside of the U.S. The Company paid Regeneron a $ 30.0 million upfront payment. As of December 31, 2024 the Company has recognized an aggregate of $ 27.5 million for regulatory and sales milestones under the agreement, of which $ 15.0 million was achieved during the year ended December 31, 2024. As these payments are for the Company’s use of intellectual property for Evkeeza for HoFH, they were recorded as intangible assets. See "Note 5. Intangible Assets, net" for additional details. Going forward, the Company is obligated to pay Regeneron up to an aggregate of $ 35.5 million of future obligations for additional regulatory and sales milestones, if achieved. The Company may share in certain costs for global trials led by Regeneron and also received the right to opt into other potential indications. Additionally, the Company pays Regeneron a transfer price fee and royalties on certain revenues. The collaboration agreement is within the scope of ASC 808 which provides guidance on the presentation and disclosure of collaborative arrangements. As the Company is the principal in sales transactions with the customer, the Company recognizes product sales and cost of sales in the period the related sales occur and the related revenue recognition criteria are met. Under the collaboration agreement, Regeneron supplies the product and charges the Company a transfer price from the low 20 % range up to 40 % on net sales, which is recognized as cost of sales in the Company’s Statement of Operations. Under the collaboration agreement, Regeneron and the Company share certain development and commercialization costs. Regeneron also receives a transfer price and royalty on net product sales revenue which is recorded in cost of sales. These amounts were recognized in the Company’s Statements of Operations in connection with the collaboration agreement with Regeneron as follows (in thousands): Year Ended December 31, 2024 2023 2022 Research and development $ ( 2,842 ) $ 7,629 $ 7,258 Cost of sales $ 8,030 $ 684 $ — The Company had collaboration payables for this arrangement included in accrued liabilities on the Consolidated Balance Sheets of $ 17.8 million and $ 10.6 million as of December 31, 2024 and December 31, 2023, respectively. Saint Louis University In November 2010, the Company entered into a license agreement with Saint Louis University, or SLU. Under the terms of this license agreement, SLU granted the Company an exclusive worldwide license to make, have made, use, import, offer for sale, and sell therapeutics related to SLU’s beta-glucuronidase product for use in the treatment of human diseases. Under the license agreement, the Company is obligated to pay to SLU a low single-digit royalty on net sales of the licensed products in Europe and Japan, subject to certain potential deductions. The Company's obligation to pay royalties to SLU in these territories continues until the expiration of any orphan drug exclusivity. Abeona In May 2022, the Company announced an exclusive License Agreement for the AAV gene therapy for UX111 with Abeona for the treatment of MPS IIIA. Under the terms of the agreement, the Company assumed responsibility for the UX111 program and in return, the Company is obligated to pay tiered royalties of up to 10 % on net sales and commercial milestone payments of up to $ 30.0 million contingent upon regulatory approval of the product. Additionally, the Company entered into an Assignment and Assumption Agreement with Abeona to transfer and assign to the Company the exclusive license agreement between Nationwide Children’s Hospital, or NCH, and Abeona for certain rights related to UX111. Under this agreement, the Company is obligated to pay up to $ 1.0 million contingent upon achievement of development and regulatory milestones as well as royalties in the low single-digits of net sales. The Company paid Abeona $ 3.1 million for prior development and transition costs which were recorded as research and development expense for the year ended December 31, 2022. Mereo In December 2020, the Company entered into a License and Collaboration Agreement with Mereo to collaborate on the development of setrusumab. Under the terms of the agreement, as amended, the Company will lead future global development of setrusumab in both pediatric and adult patients with OI. The Company was granted an exclusive license to develop and commercialize setrusumab in the U.S., Turkey, and the rest of the world, or the Ultragenyx Territory, excluding the EEA, UK, and Switzerland, or the Mereo Territory, where Mereo retains commercial rights. Each party will be responsible for post-marketing commitments in their respective territories and Ultragenyx will be responsible for commercial supply in both the Ultragenyx Territory and Mereo Territory. Upon the closing of the transactions under the License and Collaboration Agreement with Mereo in January 2021, the Company made a payment of $ 50.0 million to Mereo. To date, the Company has made payments totaling $ 9.0 million for regulatory milestones achieved. The Company is obligated to pay Mereo up to $ 245.0 million in future milestone payments, contingent upon the achievement of certain regulatory and commercial milestones. The Company pays for all global development costs and will pay a tiered double-digit percentage royalties to Mereo on net sales in the Ultragenyx Territory. Mereo will pay the Company a fixed double-digit percentage royalty on net sales in the Mereo Territory. If the Company receives and resells an FDA PRV in connection with a new drug application approval, Mereo is entitled to receive a portion of proceeds from the sale of the PRV or a cash payment from the Company, in the event the Company chooses to retain the PRV. In December 2024, the Company entered into a manufacturing and supply agreement with Mereo where it is responsible for the supply of setrusumab to Mereo in the Mereo territory. Mereo is responsible to reimburse us for a portion of the manufacturing process development costs as well as future commercial supply costs. Although Mereo is a VIE, the Company is not the primary beneficiary as it does not have the power to direct the activities that would most significantly impact the economic performance of Mereo. Prior to the achievement of certain development milestones, all consideration paid to Mereo represents rights to potential future benefits associated with Mereo’s in-process research and development activities, which have not reached technological feasibility and have no alternative future use. F or the year ended December 31, 2024, the Company recorded an offset to research and development expense of $ 0.9 million. For the year ended December 31, 2023, the Company recorded development costs of $ 9.0 million for the achievement of a clinical milestone recorded in research and development expense. University of Pennsylvania The Company has a research, collaboration, and license agreement with University of Pennsylvania School of Medicine, or Penn, which provides the terms for the Company and Penn to collaborate with respect to the pre-clinical development of gene therapy products for the treatment of certain indications. Under the agreement, Penn granted the Company an exclusive, worldwide license to certain patent rights arising out of the research program, subject to certain retained rights, and a non-exclusive, worldwide license to certain Penn intellectual property, in each case to research, develop, make, have made, use, sell, offer for sale, commercialize and import licensed products in each indication for the term of the agreement. The Company will fund the cost of the research program in accordance with a mutually agreed-upon research budget and will be responsible for clinical development, manufacturing and commercialization of each indication. The Company is obligated to make milestone payments of up to $ 5.0 million for each indication, if certain development milestones are achieved. The Company is also obligated to make milestone payments of up to $ 25.0 million per approved product, if certain commercial milestones are achieved, as well as low to mid- single-digit royalties on net sales of each licensed product. REGENXBIO, Inc. The Company has a license agreement with REGENXBIO, Inc., or REGENX, for an exclusive, sublicensable, worldwide commercial license under certain intellectual property for preclinical and clinical research and development, and commercialization of drug therapies using REGENX's licensed patents for the treatment of OTC deficiency and GSD1a. The Company will pay an annual fee and certain milestone fees per disease indication, low to mid- single-digit royalty percentages on net sales of licensed products, and milestone and sublicense fees owed by REGENX to its licensors, which are contingent upon the attainment of certain development activities as outlined in the agreement. The Company also has an option and license agreement with REGENX under which the Company has an exclusive, sublicensable, worldwide license to make, have made, use, import, sell, and offer for sale licensed products to treat Wilson disease and CDKL5 deficiency . For each disease indication, the Company is obligated to pay a nominal annual maintenance fee and up to $ 9.0 million upon achievement of various milestones, as well as mid- to high single-digit royalties on net sales of licensed products and mid- single-digit to low double-digit percentage sublicenses fees, if any. In March 2020, the Company entered into a license agreement with REGENX, for an exclusive, sublicensable, worldwide license to REGENX’s NAV AAV8 and AAV9 vectors for the development and commercialization of gene therapy treatments for a rare metabolic disorder. In return for these rights, the Company made an upfront payment of $ 7.0 million. The Company is obligated to pay nominal annual fees, milestone payments of up to $ 14.0 million contingent upon achievement, and royalties on any net sales of products incorporating the licensed intellectual property that range from a high single-digit to low double-digit royalty. Solid Biosciences, Inc. In October 2020, the Company entered into a strategic Collaboration and License Agreement with Solid Biosciences Inc., or Solid, and received an exclusive license for any pharmaceutical product that expresses Solid’s proprietary microdystrophin construct from AAV8 and variants thereof in clade E for use in the treatment of Duchenne muscular dystrophy and other diseases resulting from lack of functional dystrophin, including Becker muscular dystrophy. The Company is collaborating to develop products that combine Solid’s differentiated microdystrophin construct, the Company’s Pinnacle PCL Platform, and the Company’s AAV8 variants. Solid is providing development support and was granted an exclusive option to co-invest in products the Company develops for profit-share participation in certain territories. On a product-by-product basis, the Company is obligated to make development milestone payments of up to $ 25.0 million, regulatory milestone payments of up to $ 65.0 million, and commercial milestone payments of up to $ 165.0 million, if such milestones are achieved, as well as royalties on any net sales of products incorporating the licensed intellectual property that range from a low to mid-double-digit percentage. The royalty rate changes to mid- to high double-digit percentage if Solid decides to co-invest in the product. The Company also entered into a Stock Purchase Agreement and the Investor Agreement with Solid, pursuant to which the Company holds 521,719 shares of Solid's common stock. The Company’s investment in Solid is being accounted at fair value, as the fair value is readily determinable. The Company recorded the common stock investment at $ 26.8 million on the transaction date, which was based on the quoted market price on the closing date. Although Solid is a VIE, the Company is not the primary beneficiary as it does not have the power to direct the activities that would most significantly impact the economic performance of Solid. Prior to the achievement of certain development milestones, all consideration paid to Solid represents rights to potential future benefits associated with Solid’s in-process research and development activities, which have not reached technological feasibility and have no alternative future use. Accordingly, the remaining $ 13.2 million of the total $ 40.0 million paid as consideration was attributed to the license rights obtained and was recorded as in-process research and development expense during the year ended December 31, 2020. The changes in the fair value of the Company’s investment in Solid’s common stock were as follows (in thousands): Solid Common Stock December 31, 2022 $ 2,807 Change in fair value 397 December 31, 2023 3,204 Change in fair value ( 1,115 ) December 31, 2024 $ 2,089 Arcturus Therapeutics Holdings Inc. The Company previously held an investment in shares of common stock from Arcturus Therapeutics Holdings Inc., or Arcturus, which was accounted at fair value, as the fair value was readily determinable. During the year ended December 31, 2022, the Company sold 500,000 shares of Arcturus common stock, at a weighted-average price of $ 20.39 per share. As of December 31, 2024 and 2023, the Company held no shares of Arcturus common stock. The changes in the fair value of the Company’s equity investment in Arcturus were as follows (in thousands): Arcturus Common Stock December 31, 2021 $ 18,505 Change in fair value ( 8,411 ) Sale of shares ( 10,094 ) December 31, 2022 $ —

Leases

Leases	12 Months Ended
	Dec. 31, 2024
Lessee Disclosure [Abstract]
Leases	10. Leases The Company leases office space and research, testing and manufacturing laboratory space in various facilities in Novato and Brisbane, California, in Somerville and Woburn, Massachusetts, and in certain foreign countries, under operating agreements expiring at various dates through 2029 . Certain lease agreements include options for the Company to extend the lease for multiple renewal periods and provide for annual minimum increases in rent, usually based on a consumer price index or annual minimum increases. None of these optional periods have been considered in the determination of the right-of-use lease asset or the lease liability for the leases as the Company did not consider it reasonably certain that it would exercise any such options. The Company recognizes lease expense on a straight-line basis over the non-cancelable term of its operating leases. The variable lease expense primarily consists of common area maintenance and other operating costs. The components of lease expense were as follows (in thousands): Year Ended December 31, 2024 2023 2022 Operating lease expense $ 11,985 $ 12,883 $ 11,775 Variable lease expense 5,893 5,272 4,785 Financing: Amortization — 203 343 Interest expense — — 37 Total $ 17,878 $ 18,358 $ 16,940 Cash paid for amounts included in the measurement of operating lease liabilities for the years ended December 31, 2024, 2023, and 2022 was $ 16.1 million, $ 13.4 million, and $ 13.1 million, respectively, and was included in net cash used in operating activities in the Consolidated Statements of Cash Flows. Right-of-use lease assets were $ 25.5 million and $ 23.9 million as of December 31, 2024 and 2023, respectively, and were included in other non-current assets on the Consolidated Balance Sheets. The following table summarizes maturities of lease liabilities and the reconciliation of lease liabilities as of December 31, 2024: Year Ending December 31, Operating 2025 $ 13,831 2026 13,949 2027 9,019 2028 6,709 2029 5,589 Thereafter 467 Total future lease payments 49,564 Less: Amount representing interest ( 9,225 ) Present value of future lease payments 40,339 Less: Lease liabilities, current ( 10,297 ) Lease liabilities, non-current $ 30,042 Lease liabilities are based on the net present value of the remaining lease payments over the remaining lease term. For the years ended December 31, 2024 and 2023 , the weighted-average remaining operating lease terms were 4 years and 5 years, respectively, the weighted-average discount rates used to determine the lease liability for operating leases were 10.1 % and 9.6 %, respectively.

Liabilities for Sales of Future

Liabilities for Sales of Future Royalties	12 Months Ended
	Dec. 31, 2024
Deferred Revenue Disclosure [Abstract]
Liabilities for Sales of Future Royalties	11. Liabilities for Sales of Future Royalties In December 2019, the Company entered into a Royalty Purchase Agreement with RPI. Pursuant to the agreement, RPI paid $ 320.0 million to the Company in consideration for the right to receive royalty payments effective January 1, 2020, arising from the net sales of Crysvita in the EU, the U.K., and Switzerland under the terms of the Company’s Collaboration and License Agreement with KKC dated August 29, 2013, as amended, or the KKC Collaboration Agreement. The agreement with RPI will automatically terminate, and the payment of royalties to RPI will cease, in the event aggregate royalty payments received by RPI are equal to or greater than $ 608.0 million prior to December 31, 2030, or in the event aggregate royalty payments received by RPI are less than $ 608.0 million prior to December 31, 2030, or when aggregate royalty payments received by RPI are equal to $ 800.0 million. In July 2022, the Company entered into a Royalty Purchase Agreement with OMERS. Pursuant to the agreement, OMERS paid $ 500.0 million to the Company in consideration for the right to receive 30 % of the future royalty payments due to the Company from KKC based on net sales of Crysvita in the U.S. and Canada under the terms of the KKC Collaboration Agreement. The calculation of royalty payments to OMERS is based on net sales of Crysvita beginning in April 2023 and will expire upon the earlier of the date on which aggregate payments received by OMERS equals $ 725.0 million or the date the final royalty payment is made to the Company under the KKC Collaboration Agreement. Proceeds from these transactions were recorded as liabilities for sales of future royalties on the Consolidated Balance Sheets. Upon inception of the respective arrangements, the Company recorded $ 320.0 million and $ 500.0 million, net of transaction costs of $ 5.8 million and $ 9.1 million for RPI and OMERS, respectively. The Company records the royalty revenue arising from the net sales of Crysvita in the applicable territories as royalty revenue in the Consolidated Statements of Operations over the term of the arrangements. Royalties earned under the RPI and OMERS arrangements from inception to December 31, 2024 have been $ 99.3 million and $ 123.3 million, respectively. The Company’s effective annual interest rates were 6.2 % and 7.5 %, for RPI and OMERS, respectively, as of December 31, 2024. There are a number of factors that could materially affect the amount and timing of royalty payments from KKC in the applicable territories, most of which are not within the Company’s control. Such factors include, but are not limited to, the success of KKC’s sales and promotion of Crysvita, changing standards of care, macroeconomic and inflationary pressures, the introduction of competing products, pricing for reimbursement in various territories, manufacturing or other delays, intellectual property matters, adverse events that result in governmental health authority imposed restrictions on the use of Crysvita, significant changes in foreign exchange rates as the royalty payments are made in U.S. dollars, or USD, while significant portions of the underlying sales of Crysvita are made in currencies other than USD, and other events or circumstances that could result in reduced royalty payments from sales of Crysvita, all of which would result in a reduction of royalty revenue and the non-cash interest expense over the life of the arrangement. Conversely, if sales of Crysvita in the relevant territories are more than expected, the royalty revenue and the non-cash interest expense recorded by the Company would be greater over the term of the arrangements. The following table shows the activity within the liability account (in thousands): Liabilities for Sales of Future Royalties RPI OMERS Total December 31, 2022 $ 365,189 $ 510,250 $ 875,439 Royalty revenue ( 20,783 ) ( 38,524 ) ( 59,307 ) Non-cash interest expense 32,235 43,200 75,435 December 31, 2023 376,641 514,926 891,567 Royalty revenue ( 25,849 ) ( 59,088 ) ( 84,937 ) Non-cash interest expense 23,747 39,294 63,041 December 31, 2024 $ 374,539 $ 495,132 $ 869,671

Equity

Equity	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Equity	12. Equity At-the-Market Offerings In February 2024, the Company entered into a Sales Agreement with Cowen and Company, LLC, or Cowen, pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering proceeds up to $ 350.0 million, from time to time, in at-the-market, or ATM, offerings through Cowen. No shares were sold under this agreement during the year ended December 31, 2024. In May 2021, the Company entered into an Open Market Sale Agreement with Jefferies LLC, or Jefferies, pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering proceeds up to $ 350.0 million, from time to time, in ATM offerings through Jefferies. During the year ended December 31, 2023 , there were 1,175,584 shares sold under the ATM resulting in net proceeds of $ 53.3 million. Underwritten Public Offering In June 2024, the Company completed an underwritten public offering in which 8,782,051 shares of common stock were sold, including the exercise in full by the underwriters of their option to purchase an additional 1,346,153 shares, at a public offering price of $ 39.00 per share. In connection with the offering, the Company sold to certain investors pre-funded warrants, in lieu of common stock, to purchase 1,538,501 shares of common stock at a purchase price of $ 38.999 per pre-funded warrant, which equals the public offering price per share of common stock less the $ 0.001 exercise price per share of each pre-funded warrant. The total proceeds that the Company received from the offering were $ 381.0 million, net of underwriting discounts and commissions. The pre-funded warrants were classified as a component of permanent equity in the Company's Consolidated Balance Sheets as they are freestanding financial instruments that are immediately exercisable, do not embody an obligation for the Company to repurchase its own shares and permit the holders to receive a fixed number of shares of common stock upon exercise. All of the shares underlying the pre-funded warrants have been included in the weighted-average number of shares of common stock used to calculate net loss per share, basic and diluted, attributable to common stockholders because the shares may be issued for little or no consideration, are fully vested, and are exercisable after the original issuance date of the pre-funded warrants. As of December 31, 2024 , no ne of the pre-funded warrants had been exercised. The table below summarizes pre-funded warrants activity: Pre-funded warrants As of December 31, 2022 — Issuance of pre-funded warrants 1,666,722 As of December 31, 2023 1,666,722 Issuance of pre-funded warrants 1,538,501 As of December 31, 2024 3,205,223 In October 2023, the Company completed an underwritten public offering in which 9,833,334 shares of common stock were sold, including the exercise in full by the underwriters of their option to purchase an additional 1,500,000 shares, at a public offering price of $ 30.00 per share. In connection with the offering, the Company sold to certain investors pre-funded warrants, in lieu of common stock, to purchase 1,666,722 shares of common stock at a purchase price of $ 29.999 per pre-funded warrant, which equals the public offering price per share of common stock less the $ 0.001 exercise price per share of each pre-funded warrant. The total proceeds that the Company received from the offering were $ 326.5 million, net of underwriting discounts and commissions.

Stock-Based Awards

Stock-Based Awards	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Awards	13. Stock-Based Awards Equity Plan Awards Under the terms of the Company's 2023 Incentive Plan, or 2023 Plan, and Employment Inducement Plan, or Inducement Plan, awards may be granted at an exercise price not less than fair market value. The exercise price of an option may not be less than the fair market value. The term of an award granted under the 2023 Plan and Inducement Plan may not exceed ten years . Typically, the vesting schedule for option grants to employees provides that 1/4 of the grant vests upon the first anniversary of the date of grant, with the remainder of the shares vesting monthly thereafter at a rate of 1/48 of the total shares subject to the option. Typically, the vesting schedule for RSU grants provides that 1/4 of the grant vests upon the annual anniversary of the date of grant over the period of four years . Under the 2014 Employee Stock Purchase Plan, or ESPP, eligible employees may purchase common stock at 85 % of the lesser of the fair market value of common stock on the offering date or the purchase date with a six-month look-back feature. ESPP purchases are settled with common stock from the ESPP’s previously authorized and available pool of shares. During the year ended December 31, 2024 , the Company issued 200,539 shares of common stock under the ESPP. The table below summarizes the Company's equity plans as of December 31, 2024: Plan Year of Adoption Expiration Date, as Amended Maximum Number of Shares Authorized Shares Available for Future Issuance Employment Inducement Plan 2021 February 3, 2031 1,200,000 211,628 2023 Incentive Plan (1) 2023 June 7, 2023 10,475,837 6,139,766 2014 Employee Stock Purchase Plan 2014 June 7, 2033 7,330,914 6,409,256 (1) Maximum number of shares authorized and shares available for future issuance under the 2023 Incentive Plan include 1,975,837 shares subject to the 2014 Incentive Plan cancelled after June 7, 2023 . Stock Option Activity The following table summarizes activity under the Company’s stock option plans and related information: Options Outstanding Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding — December 31, 2023 8,787,712 $ 67.43 6 $ 7,558 Options granted 1,445,364 52.91 Options exercised ( 124,536 ) 46.06 Options cancelled ( 747,571 ) 66.68 Outstanding — December 31, 2024 9,360,969 65.54 6 1839 Vested and exercisable — December 31, 2024 6,360,538 71.27 5 729 Vested and expected to vest — December 31, 2024 9,096,200 65.95 6 1,742 The following table summarizes the Company's options exercised and vested for each of the periods indicated (in thousands except for weighted-average estimated fair value of options granted): Year Ended December 31, 2024 2023 2022 Intrinsic value of options exercised $ 862 $ 4,950 $ 2,552 Cash received from the exercise of options $ 5,736 $ 2,743 $ 6,242 Weighted-average estimated fair value of options granted $ 29.88 $ 25.53 $ 34.77 Estimated fair value of options vested $ 53,838 $ 59,663 $ 58,677 The aggregate intrinsic values of options outstanding, vested and exercisable, and vested and expected to vest were calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock. Performance Stock Options The following table summarizes activity under the Company’s Performance Stock Option, or PSO, plans and related information: PSOs Outstanding Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding — December 31, 2023 1,380,998 $ 67.37 3 $ — PSOs cancelled ( 135,707 ) 67.37 Outstanding — December 31, 2024 1,245,291 67.37 2 — Vested and exercisable — December 31, 2024 422,594 67.37 2 — Vested and expected to vest — December 31, 2024 930,420 67.37 2 — During the year ended December 31, 2022, PSOs were granted to certain nonexecutive employees. PSOs are subject to vest only if specified operational milestones are achieved and the employees’ continued service with the Company. The Company uses the Black-Scholes method to calculate the fair value at the grant date and is recognizing stock-based compensation expense for the PSOs that are expected to vest. Stock-based compensation for PSOs is recognized over the service period, beginning in the period the Company determines it is probable that a milestone will be achieved. Forfeitures of PSOs are recognized as they occur. The Company reassesses the probability of the performance condition at each reporting period and adjusts the compensation cost based on the probability assessment. As of December 31, 2024, certain operational milestones were deemed probable of achievement. The aggregate intrinsic values of PSOs outstanding, vested and exercisable, and vested and expected to vest were calculated as the difference between the exercise price of the PSOs and the fair value of the Company’s common stock. The total estimated grant date fair value of PSOs vested during the years ended December 31, 2024 and 2023, was $ 9.9 million and $ 3.4 million, respectively. No PSOs were granted or exercised during the years ended December 31, 2024 and 2023. The weighted-average estimated fair value of PSOs granted was $ 28.76 during the year ended December 31, 2022. Restricted Stock Units The following table summarizes activity under the Company’s Restricted Stock Units, or RSU, plans and related information: RSUs Outstanding Number Weighted-Average Grant Date Fair Value Unvested — December 31, 2023 3,444,112 $ 55.21 RSUs granted 3,169,688 53.06 RSUs vested ( 1,043,199 ) 59.92 RSUs cancelled ( 400,654 ) 54.13 Unvested — December 31, 2024 5,169,947 53.22 The fair value of the RSUs is determined on the grant date based on the fair value of the Company’s common stock. The fair value of the RSUs is recognized as expense ratably over the vesting period of one to four years . The total grant date fair value of the RSUs vested during the years ended December 31, 2024, 2023, and 2022 was $ 62.5 million, $ 54.6 million, and $ 47.1 million, respectively. The aggregate intrinsic value of the shares of the RSUs vested during the years ended December 31, 2024, 2023, and 2022 was $ 54.0 million, $ 33.0 million, and $ 37.8 million, respectively. Performance Stock Units The following table summarizes activity under the Company’s Performance Stock Units, or PSUs and related information: PSUs Outstanding Number Weighted-Average Grant Date Fair Value Unvested — December 31, 2023 506,106 $ 60.82 PSUs granted 274,484 62.60 PSUs vested ( 47,464 ) 72.17 PSUs cancelled ( 114,944 ) 68.07 Unvested — December 31, 2024 618,182 59.39 The fair value of the PSUs is determined on the grant date based on the fair value of the Company’s common stock, except for certain PSUs with a market vesting condition, for which fair value is estimated using a Monte Carlo simulation model. PSUs are subject to vest only if certain specified criteria are achieved and the employees’ continued service with the Company. For certain PSUs, the number of PSUs that may vest are also subject to the achievement of certain specified criteria, including both performance conditions and market conditions. As of December 31, 2024, certain specified criteria were deemed probable of achievement or already achieved. Stock-based compensation for PSUs is recognized over the service period beginning in the period the Company determines it is probable that the performance criteria will be achieved. The total grant date fair value of the PSUs vested during the years ended December 31, 2024, 2023, and 2022 was $ 3.4 million, $ 3.9 million, and $ 1.6 million, respectively, with an aggregate intrinsic value of the shares of $ 2.1 million, $ 1.3 million and $ 2.0 million, respectively. Stock-Based Compensation Expense Total stock-based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2024 2023 2022 Cost of sales $ 1,469 $ 1,166 $ 902 Research and development 86,616 74,531 74,464 Selling, general and administrative 69,971 59,516 55,002 Total stock-based compensation expense $ 158,056 $ 135,213 $ 130,368 Stock-based compensation of $ 2.6 million, $ 1.9 million, and $ 2.2 million was capitalized into inventory for the years ended December 31, 2024, 2023, and 2022, respectively. Capitalized stock-based compensation is recognized as cost of sales when the related product is sold. As of December 31, 2024 , the total unrecognized compensation expense related to unvested equity awards, net of estimated forfeitures, was $ 256.8 million, which the Company expects to recognize over an estimated weighted-average period of 2 years. In determining the estimated fair value of the stock options, PSOs and ESPP, the Company uses the Black-Scholes option-pricing model and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment to determine. Expected Term —The Company’s expected term represents the period that the Company’s stock-based awards are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term). Expected Volatility —The Company’s expected volatility is based on historical volatility over the look-back period corresponding to the expected term. Risk-Free Interest Rate —The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of option. Expected Dividend —The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero. Strike price for options awards and PSOs is equal to the closing market value of our common stock on the date of grant. The fair value of stock option awards granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2024 2023 2022 Expected term (years) 6 6 6 Expected volatility 55 % 55 % 56 % Risk-free interest rate 4.2 % 4.2 % 2.0 % Expected dividend rate 0.0 % 0.0 % 0.0 % The fair value of PSOs granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2022 Expected term in years 4 Expected volatility 57 % Risk-free interest rate 1.5 % Expected dividend rate 0.0 %

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2024
Defined Contribution Pension And Other Post Retirement Plan Disclosure [Abstract]
Defined Contribution Plan	14. Defined Contribution Plan The Company sponsors a retirement plan in which substantially all of its full-time employees in the U.S. and certain other foreign countries are eligible to participate. Eligible participants may contribute a percentage of their annual compensation to this plan, subject to statutory limitations. The Company recorded $ 9.8 million, $ 9.7 million, and $ 9.0 million as expense related to the plan for the years ended December 31, 2024, 2023, and 2022 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	15. Income Taxes The components of the Company’s loss (income) before income taxes were as follows (in thousands): Year Ended December 31, 2024 2023 2022 Domestic $ 564,072 $ 608,166 $ 703,411 Foreign 3,514 298 ( 1,686 ) Total loss before income taxes $ 567,586 $ 608,464 $ 701,725 The components of the Company’s income tax provision were as follows (in thousands): Year Ended December 31, 2024 2023 2022 Current provision for income taxes: Federal $ — $ — $ — State 224 ( 3,187 ) 6,062 International 2,745 3,127 1,274 Total current tax provision 2,969 ( 60 ) 7,336 Deferred tax provision: Federal — — — State — ( 1,608 ) ( 1,640 ) International ( 1,372 ) ( 157 ) — Total deferred tax provision ( 1,372 ) ( 1,765 ) ( 1,640 ) Total provision for (benefit from) income taxes $ 1,597 $ ( 1,825 ) $ 5,696 The Company has incurred net operating losses since inception. The Company has not reflected any benefit of such net operating loss carryforwards in the accompanying financial statements. The Company has established a full valuation allowance against its deferred tax assets due to the uncertainty surrounding the realization of such assets. Beginning in 2022, the Tax Cuts and Jobs Act of 2017 eliminated the right to deduct research and development expenditures for tax purposes in the period the expenses were incurred and instead requires all U.S. and foreign research and development expenditures to be amortized over five and 15 tax years, respectively. Due to this required capitalization of research and development expenditures and the significant taxable income generated as a result of our sale of royalties in July 2022, the Company has recorded current state income tax expense of $ 6.1 million for the year ended December 31, 2022. For the year ended December 31, 2023, the Company recognized an income tax benefit of $ 4.8 million attributable to modifications in its state apportionment methodology, and then offset by an income tax expense of $ 3.0 million from foreign jurisdictions. For the year ended December 31, 2024, the Company recognized an income tax expense of $ 0.2 million for state tax, and income tax expense of $ 1.4 million from foreign jurisdictions. The effective tax rate of our provision for income taxes differs from the federal statutory rate as follows: Year Ended December 31, 2024 2023 2022 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit — 0.8 ( 0.4 ) Federal tax credits 10.8 7.3 5.9 Other 0.1 ( 0.7 ) ( 0.1 ) Nondeductible permanent items ( 1.1 ) ( 0.3 ) ( 0.6 ) Stock-based compensation ( 1.6 ) ( 1.8 ) ( 1.2 ) Uncertain tax positions ( 2.0 ) ( 1.4 ) ( 1.2 ) Change in valuation allowance ( 27.1 ) ( 24.1 ) ( 24.0 ) Foreign rate differential ( 0.4 ) ( 0.5 ) ( 0.2 ) Provision for income taxes ( 0.3 ) % 0.3 % ( 0.8 ) % The tax effect of temporary differences that give rise to significant portions of the deferred tax assets is presented below (in thousands): Year Ended December 31, 2024 2023 Deferred tax assets: Loss carryforwards $ 309,301 $ 266,253 Tax credits 369,988 305,198 Stock options 51,939 44,795 Accruals and reserves 32,140 27,694 Fixed assets and intangibles 32,391 33,853 Liabilities for sales of future royalties 196,664 205,400 Basis difference in equity investments 8,683 8,423 Capitalized research and development costs 211,969 149,898 Other 589 281 Gross deferred tax assets 1,213,664 1,041,795 Valuation allowance ( 1,206,514 ) ( 1,035,836 ) Total deferred tax assets 7,150 5,959 Deferred tax liabilities: In-process research and development ( 30,058 ) ( 30,688 ) Right-of-use lease assets ( 5,778 ) ( 5,329 ) Gross deferred tax liabilities ( 35,836 ) ( 36,017 ) Net deferred tax liabilities $ ( 28,686 ) $ ( 30,058 ) As of December 31, 2024 and 2023 , the Company had approximately $ 1,190.5 million and $ 1,004.8 million, respectively, of federal net operating loss carryforwards available to reduce future taxable income that will begin to expire in 2031 . As of December 31, 2024 and 2023 , the Company had approximately $ 744.4 million and $ 659.9 million, respectively, of state net operating loss carryforwards available to reduce future taxable income that will begin to expire in 2031 . As of December 31, 2024 and 2023 , the Company had federal research tax credit carryforwards of approximately $ 45.1 million and $ 46.9 million, respectively, available to reduce future tax liabilities that will begin to expire in 2031 . As of December 31, 2024 and 2023 , the Company had state research credit carryforwards of $ 92.0 million and $ 74.4 million, respectively, available to reduce future tax liabilities that will be carried forward indefinitely. As of December 31, 2024 and 2023 , the Company had federal Orphan Drug Credits of $ 338.5 million and $ 269.6 million, respectively, available to reduce future tax liabilities that will begin to expire in 2031 . The Company’s ability to use net operating loss and tax credit carryforwards to reduce future taxable income and liabilities may be subject to annual limitations pursuant to Internal Revenue Code Sections 382 and 383 as a result of ownership changes in the past and future. As a result of ownership changes in 2012 and 2011, $ 3.6 million of federal net operating loss carryforwards, $ 3.6 million of state net operating loss carryforwards, and $ 0.2 million of federal tax credits are permanently limited. Deferred tax assets for net operating losses and tax credits have been reduced and a corresponding adjustment to the valuation allowance has been recorded. The valuation allowance increased by $ 170.7 million and $ 141.3 million during the years ended December 31, 2024 and 2023, respectively. The Company recorded unrecognized tax benefits for uncertainties in income taxes. A reconciliation of the Company’s unrecognized tax benefits follows (in thousands): December 31, 2024 2023 2022 Balance at beginning of year $ 79,998 $ 66,794 $ 55,360 Additions based on tax positions related to current 14,825 12,562 11,316 Additions for tax positions of prior years 2,173 642 377 Reductions for tax positions of prior years — — ( 259 ) Balance at end of year $ 96,996 $ 79,998 $ 66,794 Approximately $ 1.3 million in unrecognized tax benefits would impact the Company’s effective tax rate if recognized. The Company has elected to include interest and penalties as a component of tax expense. For the years ended December 31, 2024 and 2023, the Company recognized accrued interest and penalties of $ 0.1 million and $ 0.2 million, respectively, as a component of income tax expense. No accrued interest and penalties were recognized as a component of income tax expense during the year ended December 31, 2022. The Company does not anticipate that the amount of existing unrecognized tax benefits will significantly increase or decrease during the next year. It is the Company’s intention to reinvest the earnings of its non-U.S. subsidiaries in their operations. As of December 31, 2024 , the Company had not made a provision for any incremental foreign withholding taxes on approximately $ 13.0 million of the excess of the amount of net income for financial reporting over the tax basis of investments in foreign subsidiaries that are essentially permanent in duration. If these earnings were repatriated to the U.S., the deferred tax liability associated with these temporary differences would result in a nominal amount of withholding taxes. The Company files income tax returns in the U.S. federal, 40 state tax jurisdictions, and ten foreign countries. The federal and state income tax returns from inception to December 31, 2024 remain subject to examination.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. Commitments and Contingencies The Company has various manufacturing, construction, clinical, research, and other contracts with vendors in the conduct of the normal course of its business. Other than as noted below, contracts are terminable, with varying provisions regarding termination. If a contract with a specific vendor were to be terminated, the Company would only be obligated for the products or services that the Company had received at the time the termination became effective. Manufacturing and service contract obligations primarily relate to the manufacture of inventory for our approved products, the majority of which are due in the next 12 months . As of December 31, 2024, the aggregate payments under contractually-binding manufacturing and service agreements are as follows (in thousands): Year Ended December 31, 2025 2026 Total Manufacturing and Services $ 33,842 $ 9,145 $ 42,987 The terms of certain of the Company’s licenses, royalties, development and collaboration agreements, as well as other research and development activities, require the Company to pay potential future milestone payments based on product development success. The amount and timing of such obligations are unknown or uncertain. These potential obligations are further described in “Note 9. License and Research Agreements.” See “Note 10. Leases” for lease commitments. Contingencies In the ordinary course of business, the Company may become party to various claims and complaints. See “Item 3. Legal Proceedings” for material legal proceedings the Company is aware of. The process of resolving matters through litigation or other means is inherently uncertain, however management does not believe that any ultimate liability resulting from any of these potential claims will have a material adverse effect on its results of operations, financial position, or liquidity. Guarantees and Indemnifications The Company indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits, while the director or officer is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and bylaws. The term of the indemnification period lasts as long as a director or officer may be subject to any proceeding arising out of acts or omissions of such director and officer in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director liability insurance. This insurance allows the transfer of risk associated with the Company’s exposure and may enable it to recover a portion of any future amounts paid. The Company believes that the fair value of these indemnification obligations is minimal. Accordingly, it has not recognized any liabilities relating to these obligations for any period presented.

Related Party Transaction

Related Party Transaction	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Related Party Transaction	17. Related Party Transaction In July 2022, the Company entered into an agreement with a non-profit foundation in which two members of the Company’s board of directors, including the Company’s Chief Executive Officer, at the time also served as board members of the foundation, whereby an aggregate $ 1.0 million contribution is being paid to the foundation over a four-year period, beginning in the third quarter of 2022, to support rare disease education and awareness. As a result, the Company recorded $ 0.3 million, $ 0.3 million, and $ 0.3 million as research and development expense for this agreement for the years ended December 31, 2024, 2023, and 2022 , respectively.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Net Loss per Share	18. Net Loss per Share The following table sets forth the computation of the basic and diluted net loss per share during the years ended December 31, 2024, 2023, and 2022 (in thousands, except share and per share data): Year Ended December 31, 2024 2023 2022 Numerator: Net loss $ ( 569,183 ) $ ( 606,639 ) $ ( 707,421 ) Denominator: Weighted-average shares used to compute net loss per 90,538,118 73,543,862 69,914,225 Net loss per share, basic and diluted $ ( 6.29 ) $ ( 8.25 ) $ ( 10.12 ) The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: Year Ended December 31, 2024 2023 2022 Options to purchase common stock, 16,284,470 14,152,286 11,290,935 Employee stock purchase plan 7,790 8,450 7,581 16,292,260 14,160,736 11,298,516

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2024
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	19. Accumulated Other Comprehensive (Loss) Income Total accumulated other comprehensive (loss) income consisted of the following (in thousands): Year Ended December 31, 2024 2023 Cumulative foreign currency translation adjustment $ ( 1,650 ) $ ( 606 ) Unrealized gain (loss) on securities available-for-sale 1,007 1,253 Total accumulated other comprehensive (loss) income $ ( 643 ) $ 647

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Consolidation	Basis of Consolidation The Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries. The Company consolidates any variable interest entity, or VIE, for which it is the primary beneficiary.
Segment Reporting	Segment Reporting The Company operates as one reportable segment relating to the research, development and commercialization of its products. The segment derives its current revenues from its four commercially approved products. The Company’s Chief Operating Decision Maker, or CODM, its Chief Executive Officer and the executive leadership team, manage the Company’s operations on an integrated basis for the purposes of allocating resources. When evaluating the Company’s financial performance, the CODM regularly reviews total revenues and total expenses and makes decisions using this information on a global basis.
Use of Estimates	Use of Estimates The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP. The preparation of the Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the Consolidated Financial Statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, income taxes, stock-based compensation, revenue recognition, and the liabilities for sales of future royalties. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts. Restricted cash primarily consists of money market accounts used as collateral for the Company’s obligations under its facility leases and to guarantee the fulfillment of certain sales orders to certain government-sponsored customers. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows (in thousands): December 31, 2024 2023 2022 Cash and cash equivalents $ 173,729 $ 213,584 $ 132,944 Restricted cash included in other current assets 6,806 2,008 862 Restricted cash included in other non-current assets 3,624 3,807 3,795 Total cash, cash equivalents, and restricted cash $ 184,159 $ 219,399 $ 137,601
Marketable Debt Securities	Marketable Debt Securities All marketable debt securities have been classified as “available-for-sale” and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and reevaluates such designation as of each balance sheet date. Investments with a maturity of one year or less from the balance sheet date are reported as current marketable debt securities and investments with a maturity of greater than one year from the balance sheet date are reported as non-current marketable debt securities. Unrealized gains and losses are excluded from earnings and are reported as a component of comprehensive loss. Realized gains and losses and declines in fair value judged to be other than temporary, if any, on available-for-sale securities are included in other expense. The cost of securities sold is based on the specific-identification method. Interest on investments is included in interest income.
Equity Investments	Equity Investments The Company records investments in equity securities, other than equity method investments, at fair market value, using market quotes when readily determinable. Equity securities with no readily determinable fair values are recorded using the measurement alternative of cost adjusted for observable price changes in orderly transactions for identical or similar investments of the same issuer less impairment, if any. Investments in equity securities are recorded in other assets on the Company's Consolidated Balance Sheets. Unrealized gains and losses are reported in change in fair value of equity investments on the Company’s Consolidated Statements of Operations. The Company regularly reviews its non-marketable equity securities for indicators of impairment.
Concentration of Credit Risk, Credit Losses, and Other Risks and Uncertainties	Concentration of Credit Risk, Credit Losses, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents, and investments. The Company’s cash, cash equivalents, and investments are held by financial institutions that management believes are of high credit quality. The Company’s investment policy limits investments to fixed income securities denominated and payable in U.S. dollars such as U.S. government obligations, money market instruments and funds, corporate bonds, commercial paper, and asset-backed securities and places restrictions on maturities and concentrations by type and issuer. Such deposits may, at times, exceed federally insured limits. The Company has not experienced any losses on its deposits of cash and cash equivalents and its accounts are monitored by management to mitigate risk. The Company is exposed to credit risk in the event of default by the financial institutions holding its cash and cash equivalents, corporate issuers, and other financial instruments, to the extent recorded in the Consolidated Balance Sheets. The Company is exposed to credit losses primarily through receivables from customers and collaborators and through its available-for-sale debt securities. For trade receivables and other financial instruments, the Company uses a forward-looking expected loss model that recognizes a current period charge for losses that are expected to be incurred over the life of the financial instrument. The Company’s expected loss allowance methodology for the receivables is developed using historical collection experience, current and future economic market conditions, a review of the current aging status and financial condition of the entities. Specific allowance amounts are established to record the appropriate allowance for customers that have a higher probability of default. Balances are written off when determined to be uncollectible. The Company’s expected loss allowance methodology for the debt securities is developed by reviewing the extent of the unrealized loss, the size, term, geographical location, and industry of the issuer, the issuers’ credit ratings and any changes in those ratings, as well as reviewing current and future economic market conditions and the issuers’ current status and financial condition. For available-for-sale debt securities with unrealized losses, the losses are recognized as allowances rather than as reductions in the amortized cost of the securities. There was no allowance for losses on available-for-sale debt securities which were attributable to credit risk for the years ended December 31, 2024 and 2023. The Company is dependent on third-party manufacturers to supply products for research and development activities in its programs. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs.
Inventory	Inventory The Company values inventory at the lower of cost and net realizable value and determines the cost of inventory using the average-cost method. The Company expenses costs associated with the manufacture of product candidates prior to regulatory approval. Inventories consist of currently approved products. The Company periodically reviews its inventories for excess amounts or obsolescence and writes down obsolete or otherwise unmarketable inventory to its estimated net realizable value. Management determines excess inventory based on expected future demand. Estimates related to future demand are sensitive to significant inputs and assumptions such as acceptance by patients and physicians and the availability of formulary coverage and adequate reimbursement from private third-party payers for the product.
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the respective assets. Depreciation and amortization begins when the asset is placed in service. Interest costs incurred during the construction of major capital projects are capitalized until the underlying asset is ready to be placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation or amortization are removed from the balance sheet and the resulting gain or loss, if any, is reflected in operations. See “Note 4. Balance Sheet Components” for further disclosure on the useful lives of property, plant, and equipment.
Intangible Assets	Intangible Assets Finite-lived intangibles consist of contractual payments made for certain milestones achieved with collaboration partners. The contractual payments are recorded as intangible assets and are amortized over their estimated useful lives. The Company reviews its definite-lived intangible assets when events or circumstances may indicate that the carrying value of these assets is not recoverable and exceeds their fair value. The Company measures fair value based on the estimated future undiscounted cash flows associated with these assets in addition to other assumptions and projections that the Company deems to be reasonable and supportable. Indefinite-lived intangibles consist of acquired in-process research and development, or IPR&D. IPR&D assets represent capitalized incomplete research projects that the Company acquired through business combinations. Such assets are initially measured at their acquisition date fair values and are tested for impairment annually and whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. When development of the project is complete, which generally occurs when regulatory approval to market a product is obtained, the associated assets will be deemed finite-lived and will be amortized over a period that best reflects the economic benefits provided by these assets. If it is determined that an intangible asset becomes impaired, the carrying value is written down to its fair value with the related impairment charge recognized in Consolidated Statements of Operations in the period in which the impairment occurs. The Company has not recorded any impairments of intangible assets to date.
Goodwill	Goodwill Goodwill represents the excess of purchase price over fair value of net assets acquired in a business combination and is not amortized. Goodwill is subject to impairment testing at least annually during the fourth quarter or when a triggering event occurs that could indicate a potential impairment. If it is determined that the goodwill becomes impaired, the carrying value is written down to its fair value with the related impairment charge recognized in Consolidated Statements of Operations in the period in which the impairment occurs. The Company has not recorded any impairments of goodwill.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates its long-lived assets, including property and equipment, for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of each asset to the future undiscounted cash flows expected to result from the use of the asset and its eventual disposition. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. The Company has not recorded material impairment of any long-lived assets.
Accruals of Research and Development Costs	Accruals of Research and Development Costs The Company records accruals for estimated costs of research, preclinical and clinical studies and manufacturing development. These costs are a significant component of the Company’s research and development expenses. A substantial portion of the Company’s ongoing research and development activities are conducted by third-party service providers, including contract research organizations. The Company accrues the costs incurred under its agreements with these third parties based on actual work completed in accordance with agreements established with these third parties. The Company determines the actual costs through obtaining information from external service providers as to the progress or stage of completion of the services and the agreed-upon fee to be paid for such services.
Liabilities for Sales of Future Royalties	Liabilities for Sales of Future Royalties The Company sold the right to receive certain royalty payments from net sales of Crysvita in certain territories to RPI Finance Trust, or RPI, an affiliate of Royalty Pharma, and to OCM LS23 Holdings LP, an investment vehicle for Ontario Municipal Employees Retirement System, or OMERS, as further described in “Note 11. Liabilities for Sales of Future Royalties.” The Company recorded the liabilities at inception based upon estimated future cash flows discounted at a market rate. The liabilities are being amortized using the effective interest method over the estimated life of the applicable arrangement. In order to determine the amortization of the liabilities, the Company is required to estimate the total amount of future royalty payments to be received by the Company and paid to RPI and OMERS, subject to the capped amount, over the life of the arrangements. The excess of future estimated royalty payments (subject to the capped amount) to RPI and OMERS is recorded as non-cash interest expense over the life of the arrangements. Consequently, the Company estimates an imputed interest on the unamortized portion of the liabilities and records interest expense relating to the transactions. The Company periodically assesses the expected royalty payments using a combination of historical results, internal projections and forecasts from external sources. To the extent such payments are greater or less than the Company’s initial estimates or the timing of such payments is materially different than its original estimates, the Company employs the prospective method to adjust the amortization of the liabilities and the effective interest rate.
Revenue Recognition	Revenue Recognition Product Sales The Company sells its approved products through a limited number of distributors. Under Accounting Standards Codification, or ASC, 606, Revenue from Contracts with Customers, revenue from product sales is recognized at the point in time when control is transferred to these distributors. The Company also recognizes revenue from sales of certain products on a “named patient” basis, which are allowed in certain countries prior to the commercial approval of the product. Prior to recognizing revenue, the Company makes estimates of the transaction price, including any variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Product sales are recorded net of estimated government-mandated rebates and chargebacks, estimated product returns, and other deductions. Provisions for returns and other adjustments are provided for in the period the related revenue is recorded, as estimated by management. These reserves are based on estimates of the amounts earned or to be claimed on the related sales and are reviewed periodically and adjusted as necessary. The Company’s estimates of government mandated rebates, chargebacks, estimated product returns, and other deductions depends on the identification of key customer contract terms and conditions, as well as estimates of sales volumes to different classes of payors. If actual results vary, the Company may need to adjust these estimates, which could have a material effect on earnings in the period of the adjustment. Collaboration, License, and Royalty Revenue The Company has certain license and collaboration agreements that are within the scope of ASC 808, Collaborative Agreements , which provides guidance on the presentation and disclosure of collaborative arrangements. Generally, the classification of the transactions under the collaborative arrangements is determined based on the nature of contractual terms of the arrangement, along with the nature of the operations of the participants. The Company records its share of collaboration revenue, net of transfer pricing related to net sales in the period in which such sales occur, if the Company is considered as an agent in the arrangement. The Company is considered an agent when the collaboration partner controls the product before transfer to the customers and has the ability to direct the use of and obtain substantially all of the remaining benefits from the product. Funding received related to research and development services and commercialization costs is generally classified as a reduction of research and development expenses and selling, general and administrative expenses, respectively, in the Consolidated Statements of Operations, because the provision of such services for collaborative partners are not considered to be part of the Company’s ongoing major or central operations. The Company utilizes certain information from its collaboration partners to record collaboration revenue, including revenue from the sale of the product, associated reserves on revenue, and costs incurred for development and sales activities. For the periods covered in the financial statements presented, there have been no material changes to prior period estimates of revenues and expenses. The Company also records royalty revenues under certain of the Company’s license or collaboration agreements in exchange for license of intellectual property. As described in “Note 11. Liabilities for Sales of Future Royalties”, for certain royalty payments from net sales of Crysvita in applicable territories that were sold to RPI and OMERS, the Company records the royalty revenue on a prospective basis as non-cash royalty revenue in the Consolidated Statements of Operations over the term of the applicable arrangement. The terms of the Company’s collaboration and license agreements may contain multiple performance obligations, which may include licenses and research and development activities. The Company evaluates these agreements under ASC 606, Revenue from Contracts with Customers , to determine the distinct performance obligations. The Company analogizes to ASC 606 for the accounting for distinct performance obligations for which there is a customer relationship. Prior to recognizing revenue, the Company makes estimates of the transaction price, including variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Total consideration may include nonrefundable upfront license fees, payments for research and development activities, reimbursement of certain third-party costs, payments based upon the achievement of specified milestones, and royalty payments based on product sales derived from the collaboration. If there are multiple distinct performance obligations, the Company allocates the transaction price to each distinct performance obligation based on its relative standalone selling price. The standalone selling price is generally determined based on the prices charged to customers or using expected cost-plus margin. The Company estimates the efforts needed to complete the performance obligations and recognizes revenue by measuring the progress towards complete satisfaction of the performance obligations using input measures.
Deferred Compensation Plan	Deferred Compensation Plan The Company maintains a nonqualified deferred compensation plan whereby certain employees and members of the board of directors are able to defer certain equity awards and other compensation. Amounts deferred are invested into shares of the Company's common stock and corporate-owned life insurance. The plan complies with the provisions of Section 409A of the Internal Revenue Code. All the investments held in the plan are recorded in other non-current assets in the Consolidated Balance Sheets. The short-term portion of the corresponding liability for the plan is included in accrued expenses. The long-term portion of the liability is included in other non-current liabilities in the Consolidated Balance Sheets. Changes in the value of the deferred compensation assets and liabilities are recorded in earnings as they occur. Certain equity awards deferred under the plan are required to be settled through the issuance of Company stock. These awards are recorded as treasury stock and deferred compensation obligation within stockholders’ equity.
Leases	Leases Lease agreements are evaluated to determine whether an arrangement is or contains a lease in accordance with ASC 842, Leases . The Company determines if an arrangement includes a lease at inception. Right-of-use lease assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date. The right-of-use lease asset includes any lease payments made and excludes lease incentives. Incremental borrowing rate is used in determining the present value of future payments. The Company applies a portfolio approach to the property leases to apply an incremental borrowing rate to leases with similar lease terms. The lease terms may include options to extend or terminate the lease. The Company recognizes the options to extend the lease as part of the right-of-use lease assets and lease liabilities only if it is reasonably certain that the option would be exercised. Lease expense for minimum lease payments is recognized on a straight-line basis over the non-cancelable lease term. The Company has elected to not separate lease and non-lease components. See “Note 10. Leases” for further disclosure.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is the change in stockholders’ equity from transactions and other events and circumstances other than those resulting from investments by stockholders and distributions to stockholders. The Company’s other comprehensive loss is comprised of unrealized gains and losses on investments in available-for-sale securities and foreign currency translation adjustments.
Research and Development	Research and Development Research and development costs are expensed as incurred and consist of salaries and benefits, stock-based compensation expense, lab supplies and facility costs, as well as fees paid to other nonemployees and entities that conduct certain research and development activities on the Company’s behalf. Amounts incurred in connection with license agreements are also included in research and development expense. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred. The deferred amounts are expensed as the related goods are delivered or the services are performed.
Stock-Based Compensation	Stock-Based Compensation Stock-based awards issued to employees, including stock options, performance stock options, or PSOs, restricted stock units, or RSUs, and performance stock units, or PSUs are recorded at fair value as of the grant date and recognized as expense on a straight-line basis over the employee’s requisite service period (generally the vesting period). PSOs and PSUs vest only if certain specified criteria are achieved and the employees’ continued service requirements are met; therefore, the expense recognition occurs when the likelihood of the PSOs and PSUs being earned is deemed probable. Stock compensation expense on awards expected to vest is recognized net of estimated forfeitures.
Income Taxes	Income Taxes The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and the tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company must then assess the likelihood that the resulting deferred tax assets will be realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. Due to the Company’s lack of earnings history, the net deferred tax assets have been fully offset by a valuation allowance. In conjunction with the acquisition of Dimension Therapeutics, Inc., or Dimension, a deferred tax liability was recorded reflecting the tax impact of the difference between the book basis and tax basis of acquired IPR&D. Such deferred income tax liability is not used to offset deferred tax assets when analyzing the Company’s valuation allowance as the acquired IPR&D is considered to have an indefinite life until the Company completes or abandons development of the acquired IPR&D. The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon examination based solely on their technical merits, as the largest amount of benefit that is more likely than not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.
Foreign Currency	Foreign Currency Assets and liabilities of non-U.S. subsidiaries that operate in a local currency environment, where the local currency is the functional currency, are translated to U.S. dollars at exchange rates in effect at the balance sheet date, with the resulting translation adjustments directly recorded to a separate component of accumulated other comprehensive loss. Income and expense accounts are translated at average exchange rates for the period. Transactions which are not in the functional currency of the entity are remeasured into the functional currency and gains or losses resulting from the remeasurement recorded in other expense.
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for common stock equivalents. Shares of common stock into which pre-funded warrants may be exercised are considered outstanding for the purposes of computing basic net loss per share because the shares may be issued for little or no consideration, are fully vested and are exercisable after the original issuance date. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are antidilutive. In periods when we have incurred a net loss, options and warrants to purchase common stock are considered common stock equivalents, but have been excluded from the calculation of diluted net loss per share, as their effect is antidilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses , requiring public entities to disclose additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the impact of adopting ASU 2024-03. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures , requiring public entities to disclose information about their reportable segments’ significant expenses and other segment items on an interim and annual basis. Public entities with a single reportable segment are required to apply the disclosure requirements in ASU 2023-07, as well as all existing segment disclosures and reconciliation requirements in ASC 280 on an interim and annual basis. The Company adopted ASU 2023-07 during the year ended December 31, 2024.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows (in thousands): December 31, 2024 2023 2022 Cash and cash equivalents $ 173,729 $ 213,584 $ 132,944 Restricted cash included in other current assets 6,806 2,008 862 Restricted cash included in other non-current assets 3,624 3,807 3,795 Total cash, cash equivalents, and restricted cash $ 184,159 $ 219,399 $ 137,601

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Financial Assets Measured on Recurring Basis	The following tables set forth the fair value of the Company’s financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy (in thousands): December 31, 2024 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 113,894 $ — $ — $ 113,894 Time deposits — 10,000 — 10,000 Corporate bonds — 391,731 — 391,731 Commercial paper — 21,194 — 21,194 Asset-backed securities — 143 — 143 U.S. Government Treasury and agency securities — 158,814 — 158,814 Investment in Solid common stock 2,089 — — 2,089 Deferred compensation assets — 15,337 — 15,337 Total financial assets $ 115,983 $ 597,219 $ — $ 713,202 Financial Liabilities: Deferred compensation liabilities $ — $ 15,756 $ — $ 15,756 December 31, 2023 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 162,289 $ — $ — $ 162,289 Certificates of deposit and time deposits — 17,986 — 17,986 Corporate bonds — 215,166 — 215,166 Commercial paper — 20,620 — 20,620 Asset-backed securities — 2,712 — 2,712 U.S. Government Treasury and agency securities 57,437 259,605 — 317,042 Investment in Solid common stock 3,204 — — 3,204 Deferred compensation assets — 10,220 — 10,220 Total financial assets $ 222,930 $ 526,309 $ — $ 749,239 Financial Liabilities: Deferred compensation liabilities $ — $ 10,365 $ — $ 10,365

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Summary of Cash Equivalents and Marketable Debt Securities Classified as Available For Sale Securities	The fair values of cash equivalents and marketable debt securities classified as available-for-sale securities consisted of the following (in thousands): December 31, 2024 Amortized Gross Unrealized Estimated Cost Gains Losses Fair Value Money market funds $ 113,894 $ — $ — $ 113,894 Time deposits 10,000 — — 10,000 Corporate bonds 391,124 809 ( 202 ) 391,731 Commercial paper 21,194 — — 21,194 Asset-backed securities 143 — — 143 U.S. Government Treasury and agency securities 158,414 404 ( 4 ) 158,814 Total $ 694,769 $ 1,213 $ ( 206 ) $ 695,776 December 31, 2023 Amortized Gross Unrealized Estimated Cost Gains Losses Fair Value Money market funds $ 162,289 $ — $ — $ 162,289 Certificates of deposit and time deposits 17,986 — — 17,986 Corporate bonds 214,792 711 ( 337 ) 215,166 Commercial paper 20,620 — — 20,620 Asset-backed securities 2,715 — ( 3 ) 2,712 U.S. Government Treasury and agency securities 316,160 982 ( 100 ) 317,042 Total $ 734,562 $ 1,693 $ ( 440 ) $ 735,815
Summary of Inventory	Inventory consists of the following (in thousands): December 31, 2024 2023 Work-in-process $ 21,967 $ 18,859 Finished goods 23,040 15,110 Total inventory $ 45,007 $ 33,969
Summary of Property, Plant and Equipment, Net	Property, plant, and equipment, net consists of the following (in thousands): December 31, Useful life (years) 2024 2023 Building 20 - 30 $ 181,576 $ 181,356 Leasehold improvements Shorter of lease term or estimated useful life 58,021 58,683 Research and development equipment 5 60,233 56,347 Furniture and office equipment 5 6,475 6,419 Computer equipment and software 3 - 5 16,365 16,196 Manufacturing equipment 5 - 15 37,332 37,297 Land Not applicable 16,619 16,619 Other Varies by asset 1,790 1,050 Property, plant, and equipment, gross 378,411 373,967 Less: accumulated depreciation ( 112,482 ) ( 83,401 ) Property, plant, and equipment, net $ 265,929 $ 290,566
Summary of Accrued Liabilities	Accrued liabilities consists of the following (in thousands): December 31, 2024 2023 Research, clinical study, and manufacturing expenses $ 88,133 $ 65,326 Payroll and related expenses 94,021 82,936 Revenue related reserves 33,344 17,029 Other 25,475 31,195 Total accrued liabilities $ 240,973 $ 196,486

Intangible Assets, net (Table)

Intangible Assets, net (Table)	12 Months Ended
	Dec. 31, 2024
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Summary of Company's Intangible Assets	The Company's intangible assets were as follows: December 31, 2024 Gross Carrying Amount Weighted-Average Life (Years) Accumulated Amortization Net Carrying Amount Indefinite-lived intangibles $ 129,000 — $ — $ 129,000 Finite-lived intangibles 62,275 9 ( 12,961 ) 49,314 Total intangible assets $ 191,275 — $ ( 12,961 ) $ 178,314 December 31, 2023 Gross Carrying Amount Weighted-Average Life (Years) Accumulated Amortization Net Carrying Amount Indefinite-lived intangibles $ 129,000 — $ — $ 129,000 Finite-lived intangibles 44,775 10 ( 7,504 ) 37,271 Total intangible assets $ 173,775 — $ ( 7,504 ) $ 166,271
Schedule of Expected Amortization of the Intangible Assets	The expected amortization of the intangible assets, as of December 31, 2024, for each of the next five years and thereafter is as follows: 2025 $ 7,162 2026 7,162 2027 6,722 2028 6,282 2029 6,282 Thereafter 15,704 Total $ 49,314

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Summary of Disaggregation of Total Revenues	The following table disaggregates total revenues from external customers by product sales, royalty revenue, and collaboration and license revenue (in thousands): Year Ended December 31, 2024 2023 2022 Product sales: Crysvita $ 134,709 $ 75,697 $ 42,678 Dojolvi 88,194 70,633 55,612 Evkeeza 32,162 3,642 — Mepsevii 30,350 30,441 20,637 Total product sales 285,415 180,413 118,927 Crysvita royalty revenue 274,815 182,652 21,692 Collaboration and license revenue: Crysvita collaboration revenue in Profit-Share Territory — 69,705 215,024 Other — 1,479 7,686 Total collaboration and license revenue — 71,184 222,710 Total revenues $ 560,230 $ 434,249 $ 363,329 The following table disaggregates total revenues based on geographic location (in thousands): Year Ended December 31, 2024 2023 2022 North America $ 340,463 $ 307,149 $ 281,088 Latin America 130,713 77,342 44,711 Europe, Middle East, and Africa 80,124 47,534 36,369 Asia-Pacific 8,930 2,224 1,161 Total revenues $ 560,230 $ 434,249 $ 363,329
Schedule of Sales-Related Accruals and Allowances	The following table presents the activity and ending balances for product sales related accruals and allowances (in thousands): Year Ended December 31, 2024 2023 2022 Balance of product sales reserve at beginning of year $ 17,029 $ 11,487 $ 7,181 Provisions 38,102 18,761 13,525 Payments ( 21,391 ) ( 12,746 ) ( 9,613 ) Adjustments ( 434 ) ( 473 ) 394 Balance of product sales reserve at end of year $ 33,306 $ 17,029 $ 11,487
Summary of Changes in Contract Liabilities	The following table presents changes in the contract liabilities for the years ended December 31, 2023 (in thousands): December 31, 2023 Balance of contract liabilities at beginning of period $ 1,479 Additions — Deductions ( 1,479 ) Balance of contract liabilities at end of period, net $ —

Investment in Amlogenyx. Inc. (

Investment in Amlogenyx. Inc. (Tables)	12 Months Ended
	Dec. 31, 2024
Investments, All Other Investments [Abstract]
Changes in the Carrying Value of Noncontrolling Interest	Changes in the carrying value of noncontrolling interest for the year ended December 31, 2024, were as follows: Noncontrolling Interest As of December 31, 2023 $ — Issuance of equity from noncontrolling interest 7,000 As of December 31, 2024 $ 7,000

License and Research Agreemen_2

License and Research Agreements (Tables)	12 Months Ended
	Dec. 31, 2024
Share of Collaboration and Royalty Revenue Related to Crysvita	Total Crysvita revenue was as follows (in thousands): Year Ended December 31, 2024 2023 2022 Product sales $ 134,709 $ 75,697 $ 42,678 Revenue in profit-share territory: Royalty revenue 174,276 113,288 — Non-cash royalty revenue 74,690 48,581 — Collaboration revenue — 69,705 215,024 Total revenue in Profit-Share Territory 248,966 231,574 215,024 Non-cash royalty revenue in European Territory 25,849 20,783 21,692 Total Crysvita revenue $ 409,524 $ 328,054 $ 279,394
Kyowa Kirin Collaboration
Schedule of Cost Sharing Payments	These amounts were recognized in the Company’s Statements of Operations in connection with the collaboration agreement with KKC as follows (in thousands): Year Ended December 31, 2024 2023 2022 Research and development $ ( 3,670 ) $ ( 6,510 ) $ ( 15,974 ) Selling, general and administrative $ ( 4,082 ) $ ( 17,199 ) $ ( 37,217 ) Cost of sales $ 46,027 $ 18,476 $ 13,250
Regeneron Pharmaceuticals Inc
Schedule of Cost Sharing Payments	These amounts were recognized in the Company’s Statements of Operations in connection with the collaboration agreement with Regeneron as follows (in thousands): Year Ended December 31, 2024 2023 2022 Research and development $ ( 2,842 ) $ 7,629 $ 7,258 Cost of sales $ 8,030 $ 684 $ —
Solid Biosciences, Inc.
Schedule of Changes in Fair Value of Equity Investment	The changes in the fair value of the Company’s investment in Solid’s common stock were as follows (in thousands): Solid Common Stock December 31, 2022 $ 2,807 Change in fair value 397 December 31, 2023 3,204 Change in fair value ( 1,115 ) December 31, 2024 $ 2,089
Arcturus
Schedule of Changes in Fair Value of Equity Investment	The changes in the fair value of the Company’s equity investment in Arcturus were as follows (in thousands): Arcturus Common Stock December 31, 2021 $ 18,505 Change in fair value ( 8,411 ) Sale of shares ( 10,094 ) December 31, 2022 $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2024
Lessee Disclosure [Abstract]
Summary of Components of Lease Expense	The components of lease expense were as follows (in thousands): Year Ended December 31, 2024 2023 2022 Operating lease expense $ 11,985 $ 12,883 $ 11,775 Variable lease expense 5,893 5,272 4,785 Financing: Amortization — 203 343 Interest expense — — 37 Total $ 17,878 $ 18,358 $ 16,940
Schedule of Maturities of Lease Liabilities and the Reconciliation of Lease Liabilities	The following table summarizes maturities of lease liabilities and the reconciliation of lease liabilities as of December 31, 2024: Year Ending December 31, Operating 2025 $ 13,831 2026 13,949 2027 9,019 2028 6,709 2029 5,589 Thereafter 467 Total future lease payments 49,564 Less: Amount representing interest ( 9,225 ) Present value of future lease payments 40,339 Less: Lease liabilities, current ( 10,297 ) Lease liabilities, non-current $ 30,042

Liabilities for Sales of Futu_2

Liabilities for Sales of Future Royalties (Tables)	12 Months Ended
	Dec. 31, 2024
Deferred Revenue Disclosure [Abstract]
Schedule of Activity Within Liability for Sale of Future Royalties	The following table shows the activity within the liability account (in thousands): Liabilities for Sales of Future Royalties RPI OMERS Total December 31, 2022 $ 365,189 $ 510,250 $ 875,439 Royalty revenue ( 20,783 ) ( 38,524 ) ( 59,307 ) Non-cash interest expense 32,235 43,200 75,435 December 31, 2023 376,641 514,926 891,567 Royalty revenue ( 25,849 ) ( 59,088 ) ( 84,937 ) Non-cash interest expense 23,747 39,294 63,041 December 31, 2024 $ 374,539 $ 495,132 $ 869,671

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Summary of Pre- Funded Warrants Activity	The table below summarizes pre-funded warrants activity: Pre-funded warrants As of December 31, 2022 — Issuance of pre-funded warrants 1,666,722 As of December 31, 2023 1,666,722 Issuance of pre-funded warrants 1,538,501 As of December 31, 2024 3,205,223

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	12 Months Ended
	Dec. 31, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Company's Equity Plans	The table below summarizes the Company's equity plans as of December 31, 2024: Plan Year of Adoption Expiration Date, as Amended Maximum Number of Shares Authorized Shares Available for Future Issuance Employment Inducement Plan 2021 February 3, 2031 1,200,000 211,628 2023 Incentive Plan (1) 2023 June 7, 2023 10,475,837 6,139,766 2014 Employee Stock Purchase Plan 2014 June 7, 2033 7,330,914 6,409,256 (1) Maximum number of shares authorized and shares available for future issuance under the 2023 Incentive Plan include 1,975,837 shares subject to the 2014 Incentive Plan cancelled after June 7, 2023 .
Summary of Activity Under Stock Option Plans Including 2011 Plan, 2014 Plan and 2023 Plan	Stock Option Activity The following table summarizes activity under the Company’s stock option plans and related information: Options Outstanding Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding — December 31, 2023 8,787,712 $ 67.43 6 $ 7,558 Options granted 1,445,364 52.91 Options exercised ( 124,536 ) 46.06 Options cancelled ( 747,571 ) 66.68 Outstanding — December 31, 2024 9,360,969 65.54 6 1839 Vested and exercisable — December 31, 2024 6,360,538 71.27 5 729 Vested and expected to vest — December 31, 2024 9,096,200 65.95 6 1,742
Summary of Company's Options Exercised and Vested	The following table summarizes the Company's options exercised and vested for each of the periods indicated (in thousands except for weighted-average estimated fair value of options granted): Year Ended December 31, 2024 2023 2022 Intrinsic value of options exercised $ 862 $ 4,950 $ 2,552 Cash received from the exercise of options $ 5,736 $ 2,743 $ 6,242 Weighted-average estimated fair value of options granted $ 29.88 $ 25.53 $ 34.77 Estimated fair value of options vested $ 53,838 $ 59,663 $ 58,677
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2024 2023 2022 Cost of sales $ 1,469 $ 1,166 $ 902 Research and development 86,616 74,531 74,464 Selling, general and administrative 69,971 59,516 55,002 Total stock-based compensation expense $ 158,056 $ 135,213 $ 130,368
Fair Value of Stock Option Awards Granted Estimated Using Black-Scholes Option-Pricing Model	The fair value of stock option awards granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2024 2023 2022 Expected term (years) 6 6 6 Expected volatility 55 % 55 % 56 % Risk-free interest rate 4.2 % 4.2 % 2.0 % Expected dividend rate 0.0 % 0.0 % 0.0 % The fair value of PSOs granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2022 Expected term in years 4 Expected volatility 57 % Risk-free interest rate 1.5 % Expected dividend rate 0.0 %
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Activity Under Stock Units from 2014 Plan	The following table summarizes activity under the Company’s Restricted Stock Units, or RSU, plans and related information: RSUs Outstanding Number Weighted-Average Grant Date Fair Value Unvested — December 31, 2023 3,444,112 $ 55.21 RSUs granted 3,169,688 53.06 RSUs vested ( 1,043,199 ) 59.92 RSUs cancelled ( 400,654 ) 54.13 Unvested — December 31, 2024 5,169,947 53.22
Performance Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Activity Under Stock Units from 2014 Plan	The following table summarizes activity under the Company’s Performance Stock Units, or PSUs and related information: PSUs Outstanding Number Weighted-Average Grant Date Fair Value Unvested — December 31, 2023 506,106 $ 60.82 PSUs granted 274,484 62.60 PSUs vested ( 47,464 ) 72.17 PSUs cancelled ( 114,944 ) 68.07 Unvested — December 31, 2024 618,182 59.39
Performance Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Activity Under Stock Option Plans Including 2011 Plan, 2014 Plan and 2023 Plan	The following table summarizes activity under the Company’s Performance Stock Option, or PSO, plans and related information: PSOs Outstanding Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding — December 31, 2023 1,380,998 $ 67.37 3 $ — PSOs cancelled ( 135,707 ) 67.37 Outstanding — December 31, 2024 1,245,291 67.37 2 — Vested and exercisable — December 31, 2024 422,594 67.37 2 — Vested and expected to vest — December 31, 2024 930,420 67.37 2 —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Components of Company's Loss (Income) Before Income Taxes	The components of the Company’s loss (income) before income taxes were as follows (in thousands): Year Ended December 31, 2024 2023 2022 Domestic $ 564,072 $ 608,166 $ 703,411 Foreign 3,514 298 ( 1,686 ) Total loss before income taxes $ 567,586 $ 608,464 $ 701,725
Components of Company's Income Tax Provision	The components of the Company’s income tax provision were as follows (in thousands): Year Ended December 31, 2024 2023 2022 Current provision for income taxes: Federal $ — $ — $ — State 224 ( 3,187 ) 6,062 International 2,745 3,127 1,274 Total current tax provision 2,969 ( 60 ) 7,336 Deferred tax provision: Federal — — — State — ( 1,608 ) ( 1,640 ) International ( 1,372 ) ( 157 ) — Total deferred tax provision ( 1,372 ) ( 1,765 ) ( 1,640 ) Total provision for (benefit from) income taxes $ 1,597 $ ( 1,825 ) $ 5,696
Effective Tax Rate of Provision for Income Taxes from Federal Statutory Rate	The effective tax rate of our provision for income taxes differs from the federal statutory rate as follows: Year Ended December 31, 2024 2023 2022 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit — 0.8 ( 0.4 ) Federal tax credits 10.8 7.3 5.9 Other 0.1 ( 0.7 ) ( 0.1 ) Nondeductible permanent items ( 1.1 ) ( 0.3 ) ( 0.6 ) Stock-based compensation ( 1.6 ) ( 1.8 ) ( 1.2 ) Uncertain tax positions ( 2.0 ) ( 1.4 ) ( 1.2 ) Change in valuation allowance ( 27.1 ) ( 24.1 ) ( 24.0 ) Foreign rate differential ( 0.4 ) ( 0.5 ) ( 0.2 ) Provision for income taxes ( 0.3 ) % 0.3 % ( 0.8 ) %
Schedule of Tax Effect of Temporary Differences to Significant Portions of Deferred Tax Assets	The tax effect of temporary differences that give rise to significant portions of the deferred tax assets is presented below (in thousands): Year Ended December 31, 2024 2023 Deferred tax assets: Loss carryforwards $ 309,301 $ 266,253 Tax credits 369,988 305,198 Stock options 51,939 44,795 Accruals and reserves 32,140 27,694 Fixed assets and intangibles 32,391 33,853 Liabilities for sales of future royalties 196,664 205,400 Basis difference in equity investments 8,683 8,423 Capitalized research and development costs 211,969 149,898 Other 589 281 Gross deferred tax assets 1,213,664 1,041,795 Valuation allowance ( 1,206,514 ) ( 1,035,836 ) Total deferred tax assets 7,150 5,959 Deferred tax liabilities: In-process research and development ( 30,058 ) ( 30,688 ) Right-of-use lease assets ( 5,778 ) ( 5,329 ) Gross deferred tax liabilities ( 35,836 ) ( 36,017 ) Net deferred tax liabilities $ ( 28,686 ) $ ( 30,058 )
Unrecognized Tax Benefits	A reconciliation of the Company’s unrecognized tax benefits follows (in thousands): December 31, 2024 2023 2022 Balance at beginning of year $ 79,998 $ 66,794 $ 55,360 Additions based on tax positions related to current 14,825 12,562 11,316 Additions for tax positions of prior years 2,173 642 377 Reductions for tax positions of prior years — — ( 259 ) Balance at end of year $ 96,996 $ 79,998 $ 66,794

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Summary of Aggregate Payments under Contractually Binding Manufacturing and Service Agreements	As of December 31, 2024, the aggregate payments under contractually-binding manufacturing and service agreements are as follows (in thousands): Year Ended December 31, 2025 2026 Total Manufacturing and Services $ 33,842 $ 9,145 $ 42,987

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss per Share	The following table sets forth the computation of the basic and diluted net loss per share during the years ended December 31, 2024, 2023, and 2022 (in thousands, except share and per share data): Year Ended December 31, 2024 2023 2022 Numerator: Net loss $ ( 569,183 ) $ ( 606,639 ) $ ( 707,421 ) Denominator: Weighted-average shares used to compute net loss per 90,538,118 73,543,862 69,914,225 Net loss per share, basic and diluted $ ( 6.29 ) $ ( 8.25 ) $ ( 10.12 )
Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share	The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: Year Ended December 31, 2024 2023 2022 Options to purchase common stock, 16,284,470 14,152,286 11,290,935 Employee stock purchase plan 7,790 8,450 7,581 16,292,260 14,160,736 11,298,516

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2024
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Total Accumulated Other Comprehensive Income (Loss)	Total accumulated other comprehensive (loss) income consisted of the following (in thousands): Year Ended December 31, 2024 2023 Cumulative foreign currency translation adjustment $ ( 1,650 ) $ ( 606 ) Unrealized gain (loss) on securities available-for-sale 1,007 1,253 Total accumulated other comprehensive (loss) income $ ( 643 ) $ 647

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Details)	12 Months Ended
	Dec. 31, 2024 Segment
Organization And Nature Of Business [Line Items]
Number of reportable segments	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents	$ 173,729	[1]	$ 213,584	[1]	$ 132,944
Restricted cash included in other current assets	$ 6,806		$ 2,008		$ 862
Restricted Cash and Cash Equivalents, Current, Asset, Statement of Financial Position [Extensible List]	Other assets		Other assets		Other assets
Restricted cash included in other non-current assets	$ 3,624		$ 3,807		$ 3,795
Restricted Cash and Cash Equivalents, Noncurrent, Asset, Statement of Financial Position [Extensible List]	Other assets		Other assets		Other assets
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 184,159		$ 219,399		$ 137,601	$ 309,585
[1] The Company's Consolidated Balance Sheet as of December 31, 2024 includes $ 13.5 million in cash and cash equivalents that can be used only to settle obligations of the consolidated variable interest entity. See "Note 7. Investment in Amlogenyx Inc."

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) Segment	Dec. 31, 2023 USD ($)
Accounting Policies [Abstract]
Number of reportable segments | Segment	1
Credit losses recorded for receivables	$ 0	$ 0
Unrecognized tax benefits related to interest or penalties	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	$ 713,202	$ 749,239
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	115,983	222,930
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	597,219	526,309
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	113,894	162,289
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	113,894	162,289
Asset-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	143	2,712
Asset-backed Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	143	2,712
Certificates of Deposit and Time Deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value		17,986
Certificates of Deposit and Time Deposits | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value		17,986
Time Deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	10,000
Time Deposits | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	10,000
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	391,731	215,166
Corporate Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	391,731	215,166
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	21,194	20,620
Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	21,194	20,620
U.S. Government Treasury and Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	158,814	317,042
U.S. Government Treasury and Agency Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value		57,437
U.S. Government Treasury and Agency Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	158,814	259,605
Investments in Solid Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	2,089	3,204
Investments in Solid Common Stock | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	2,089	3,204
Deferred compensation assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	15,337	10,220
Deferred compensation assets | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	15,337	10,220
Deferred compensation liabilities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	15,756	10,365
Deferred compensation liabilities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	$ 15,756	$ 10,365

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Short-Term Debt [Member]
Schedule Of Available For Sale Securities [Line Items]
Deferred compensation liabilities	$ 0.6	$ 0.2
Long-Term Debt [Member]
Schedule Of Available For Sale Securities [Line Items]
Deferred compensation liabilities	$ 15.2	$ 10.1

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Cash Equivalents and Marketable Debt Securities Classified as Available For Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 694,769	$ 734,562
Gross Unrealized Gains	1,213	1,693
Gross Unrealized Losses	(206)	(440)
Estimated Fair Value	695,776	735,815
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	113,894	162,289
Estimated Fair Value	113,894	162,289
Asset-backed Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	143	2,715
Gross Unrealized Losses		(3)
Estimated Fair Value	143	2,712
Certificates of Deposit and Time Deposits
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		17,986
Estimated Fair Value		17,986
Time Deposits
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	10,000
Estimated Fair Value	10,000
Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	391,124	214,792
Gross Unrealized Gains	809	711
Gross Unrealized Losses	(202)	(337)
Estimated Fair Value	391,731	215,166
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	21,194	20,620
Estimated Fair Value	21,194	20,620
U.S. Government Treasury and Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	158,414	316,160
Gross Unrealized Gains	404	982
Gross Unrealized Losses	(4)	(100)
Estimated Fair Value	$ 158,814	$ 317,042

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Depreciation expense	$ 30.1	$ 22.2	$ 15
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities remaining contractual maturities	3 years

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Inventory, Net [Abstract]
Work-in-process	$ 21,967	$ 18,859
Finished goods	23,040	15,110
Total inventory	$ 45,007	$ 33,969

Balance Sheet Components - Su_3

Balance Sheet Components - Summary of Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 378,411	$ 373,967
Less accumulated depreciation	(112,482)	(83,401)
Property, plant and equipment, net	265,929	290,566
Building
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 181,576	$ 181,356
Building | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives (years)	20 years	20 years
Building | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives (years)	30 years	30 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 58,021	$ 58,683
Property, plant and equipment, estimated useful lives	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Research and Development Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 60,233	$ 56,347
Property, plant and equipment, estimated useful lives (years)	5 years	5 years
Furniture and Office Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 6,475	$ 6,419
Property, plant and equipment, estimated useful lives (years)	5 years	5 years
Computer Equipment and Software
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 16,365	$ 16,196
Computer Equipment and Software | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives (years)	3 years	3 years
Computer Equipment and Software | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives (years)	5 years	5 years
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 37,332	$ 37,297
Manufacturing Equipment | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives (years)	5 years	5 years
Manufacturing Equipment | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, estimated useful lives (years)	15 years	15 years
Land
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 16,619	$ 16,619
Other
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 1,790	$ 1,050

Balance Sheet Components - Su_4

Balance Sheet Components - Summary of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Research, clinical study, and manufacturing expenses	$ 88,133	$ 65,326
Payroll and related expenses	94,021	82,936
Revenue related reserves	33,344	17,029
Other	25,475	31,195
Total accrued liabilities	$ 240,973	$ 196,486

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Details) 1 - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
IPR&D Assets
Indefinite-Lived Intangible Assets [Line Items]
Business combination recognized intangible assets	$ 129	$ 129

Intangible Assets, Net - Addi_2

Intangible Assets, Net - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended			48 Months Ended
	Jan. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2024
Finite Lived Intangible Assets Line Items
Upfront payment and milestones achieved	$ 57.5
Acquired Finite Lived Intangible Assets Weighted Average Useful Life		9 years
Regulatory milestone payments achieved					$ 9
Cost of sales
Finite Lived Intangible Assets Line Items
Costs of sales related to amortization of intangible asset		$ 5.5	$ 3.8	$ 3.2
Dimension
Finite Lived Intangible Assets Line Items
Intangible assets, remaining amortization period		6 years			6 years
Regulatory milestone payments achieved		$ 4.8

Intangible Assets, Net - Summar

Intangible Assets, Net - Summary of Company's Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Finite and Indefinite Lived Intangible Assets [Line Items]
Intangible assets - Gross carrying amount	$ 191,275	$ 173,775
Intangible assets - Accumulated Amortization	(12,961)	(7,504)
Intangible assets - Net Carrying Amount	178,314	166,271
Indefinite-lived Intangible Assets
Schedule of Finite and Indefinite Lived Intangible Assets [Line Items]
Intangible assets - Gross carrying amount	129,000	129,000
Intangible assets - Net Carrying Amount	129,000	129,000
Finite lived intangible assets
Schedule of Finite and Indefinite Lived Intangible Assets [Line Items]
Intangible assets - Gross carrying amount	$ 62,275	$ 44,775
Intangible assets - Weighted Average Life	9 years	10 years
Intangible assets - Accumulated Amortization	$ (12,961)	$ (7,504)
Intangible assets - Net Carrying Amount	$ 49,314	$ 37,271

Intangible Assets, Net - Schedu

Intangible Assets, Net - Schedule of Expected Amortization of the Intangible Assets (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Intangible Assets, Net (Excluding Goodwill) [Abstract]
2025	$ 7,162
2026	7,162
2027	6,722
2028	6,282
2029	6,282
Thereafter	15,704
Total	$ 49,314

Revenue - Summary of Disaggrega

Revenue - Summary of Disaggregation of Total Revenues from Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Total revenues	$ 560,230	$ 434,249	$ 363,329
Collaboration and license
Disaggregation Of Revenue [Line Items]
Total revenues	0	71,184	222,710
Collaboration and license | Crysvita
Disaggregation Of Revenue [Line Items]
Total revenues	0	69,705	215,024
Collaboration and license | Other
Disaggregation Of Revenue [Line Items]
Total revenues	0	1,479	7,686
Product Revenue
Disaggregation Of Revenue [Line Items]
Total revenues	285,415	180,413	118,927
Product Revenue | Crysvita
Disaggregation Of Revenue [Line Items]
Total revenues	134,709	75,697	42,678
Product Revenue | Mepsevii
Disaggregation Of Revenue [Line Items]
Total revenues	30,350	30,441	20,637
Product Revenue | Dojolvi
Disaggregation Of Revenue [Line Items]
Total revenues	88,194	70,633	55,612
Product Revenue | Evkeeza
Disaggregation Of Revenue [Line Items]
Total revenues	32,162	3,642	0
Royalty revenue
Disaggregation Of Revenue [Line Items]
Total revenues	274,815	182,652	21,692
Royalty revenue | Crysvita
Disaggregation Of Revenue [Line Items]
Total revenues	$ 274,815	$ 182,652	$ 21,692

Revenue - Summary of Disaggre_2

Revenue - Summary of Disaggregation of Total Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Total revenues	$ 560,230	$ 434,249	$ 363,329
North America
Disaggregation Of Revenue [Line Items]
Total revenues	340,463	307,149	281,088
Latin America
Disaggregation Of Revenue [Line Items]
Total revenues	130,713	77,342	44,711
Europe, Middle East, and Africa
Disaggregation Of Revenue [Line Items]
Total revenues	80,124	47,534	36,369
Asia-Pacific
Disaggregation Of Revenue [Line Items]
Total revenues	$ 8,930	$ 2,224	$ 1,161

Revenue - Schedule of Sales-Rel

Revenue - Schedule of Sales-Related Accruals and Allowances (Details) - Product sales - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Balance of product sales reserve at beginning of year	$ 17,029	$ 11,487	$ 7,181
Provisions	38,102	18,761	13,525
Payments	(21,391)	(12,746)	(9,613)
Adjustments	(434)	(473)	394
Balance of product sales reserve at end of year	$ 33,306	$ 17,029	$ 11,487

Revenue - Summary of Changes in

Revenue - Summary of Changes in Contract Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Disaggregation of Revenue [Abstract]
Balance of contract liabilities at beginning of period	$ 1,479
Additions	0
Deductions	(1,479)
Balance of contract liabilities at end of period, net	$ 0

Revenue - Additional Informatio

Revenue - Additional Information (Details)	Dec. 31, 2024	Dec. 31, 2023
Customer One
Disaggregation of Revenue [Line Items]
Percentage of gross accounts receivable balance	70%	53%

Investment in Amlogenyx. Inc. -

Investment in Amlogenyx. Inc. - Changes in the Carrying Value of Noncontrolling Interest (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)
Investments, All Other Investments [Abstract]
As of December 31, 2023	$ 0
Issuance of equity from noncontrolling interest	7,000
As of December 31, 2024	$ 7,000

Investment in Amlogenyx. Inc._2

Investment in Amlogenyx. Inc. - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2024	Dec. 31, 2024	Jul. 31, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Total assets		$ 1,503,456		$ 1,491,013
Total liabilities		1,241,159		$ 1,215,599
Amlogenyx Inc [Member]
Schedule of Investments [Line Items]
Shares received			9,000,000
Contributed by affiliated entities			$ 7,000
Total assets		13,500
Total liabilities		$ 100
Amlogenyx Inc [Member] | 2024 Equity Incentive Plan [Member]
Schedule of Investments [Line Items]
Stock options, granted	778,500
Shares authorised for issuance	1,358,060
Amlogenyx Inc [Member] | Third-Party Investor [Member]
Schedule of Investments [Line Items]
Estimated fair value			$ 7,000
Amlogenyx Inc [Member] | Series Seed Preferred Stock [Member]
Schedule of Investments [Line Items]
Shares received			1,600,000

GeneTx Acquisition - Additional

GeneTx Acquisition - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Future milestones payable		$ 75,000
Acquired in-process research and development		0	$ 0	$ 75,033
GeneTx [Member]
Business Acquisition [Line Items]
Business acquisition, consideration transferred	$ 75,000
Outstanding Cash and Cash Equivalents Acquired	15,600
Amount on adjustments for working capital and transaction expenses	600
Payments to Acquire Businesses, Gross	$ 91,200
Milestone payments received		30,000
Eligible future milestone payments		85,000
Texas A&M University [Member]
Business Acquisition [Line Items]
Clinical Milestone Aggregate		500
Collaboration payables		500	$ 0
Texas A&M University [Member] | Maximum
Business Acquisition [Line Items]
Future contingent milestone payments		23,000
Annual License Fee Payment		$ 2,000

License and Research Agreemen_3

License and Research Agreements - Kyowa Kirin Co., Ltd. - Additional Information (Details) - License Agreement - USD ($) $ in Millions		12 Months Ended		113 Months Ended
	Jul. 01, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Royalty Revenue in European Territory
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty on net sales receives		10%
Kyowa Kirin Collaboration
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Profit loss sharing percentage on net sales			30%	35%
Kyowa Kirin Collaboration | Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Tiered double-digit revenue share percentage entitled to receive		20%
Kyowa Kirin Collaboration | Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Tiered double-digit revenue share percentage entitled to receive		30%
Kyowa Kirin Collaboration | Other Current Assets
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License agreement other receivables		$ 1.8	$ 1.1
Kyowa Kirin Collaboration | Profit Share Revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License agreement accounts receivable		85.4	39.2
Kyowa Kirin Collaboration | Commercial And Development Activity Reimbursements [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License agreement accrued liabilities		$ 7.1	$ 5.3
Kyowa Kirin Collaboration | Profit Share Territory
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Remaining profit or loss share percentage on commercializing products		50%
Percentage of right to receive royalty payments on net sales	30%

License and Research Agreemen_4

License and Research Agreements - Baylor Research Institute - Additional Information (Details) - Baylor Research Institute - Development Milestones - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future contingent milestone payments		$ 7.5
Research and Development Expense
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent milestone payment	$ 2.5

License and Research Agreemen_5

License and Research Agreements - REGENXBIO, Inc. - Additional Information (Details) - REGENXBIO, Inc. - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2024
Option and License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future contingent milestone payments		$ 9
Option and license agreement description		The Company also has an option and license agreement with REGENX under which the Company has an exclusive, sublicensable, worldwide license to make, have made, use, import, sell, and offer for sale licensed products to treat Wilson disease and CDKL5 deficiency
License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future contingent milestone payments		$ 14
Upfront payment for in-process research and development expense	$ 7

License and Research Agreemen_6

License and Research Agreements - University of Pennsylvania - Additional Information (Details) - University of Pennsylvania School of Medicine (Penn) $ in Millions	Dec. 31, 2024 USD ($)
Research Collaboration and License Agreement Development Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future contingent milestone payments	$ 5
Research Collaboration and License Agreement Commercial Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future contingent milestone payments	$ 25

License and Research Agreemen_7

License and Research Agreements - Arcturus Therapeutics Holdings Inc. - Additional Information (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2024	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock. per share		$ 0.001	$ 0.001
Arcturus Therapeutics Holdings Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock shares sold	500,000
Common stock. per share	$ 20.39
Number of common stock held		0

License and Research Agreemen_8

License and Research Agreements - Mereo - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended			48 Months Ended
	Jan. 31, 2021	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development		$ 697,865	$ 648,449	$ 705,789
Regulatory milestone payments achieved					$ 9,000
License and Collaboration Agreement | Mereo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Research and development			$ 9,000
Offset to research and development expense		$ (900)
Payments made under agreement	$ 50,000
License and Collaboration Agreement | Maximum | Mereo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Future contingent milestone payments	$ 245,000

License and Research Agreemen_9

License and Research Agreements - Regeneron - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended			36 Months Ended	48 Months Ended
	Jan. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2024	Dec. 31, 2024
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Regulatory milestone payments achieved						$ 9,000
Cost of sales		$ 76,728	$ 45,209	$ 28,320
Regeneron Pharmaceuticals Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payments of collaboration	$ 30,000
Regulatory milestone payments achieved		15,000			$ 27,500
Eligible future milestone payments		35,500			35,500	35,500
Accrued collaboration payables		$ 17,800	$ 10,600		$ 17,800	$ 17,800
Maximum | Regeneron Pharmaceuticals Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Profit loss sharing percentage on net sales	40%
Minimum | Regeneron Pharmaceuticals Inc
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Profit loss sharing percentage on net sales	20%

License and Research Agreeme_10

License and Research Agreements - Abeona - Additional Information (Details) - Abeona - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2022	Dec. 31, 2024	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development and transition costs			$ 3.1
Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Eligible future milestone payments		$ 1
License and Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty on net sales receives		10%
Commercial milestone payments	$ 30

License and Research Agreeme_11

License and Research Agreements - Solid Biosciences, Inc. - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2020	Dec. 31, 2020	Dec. 31, 2024	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock investment value			$ 92	$ 82
Solid Biosciences, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Remaining consideration paid		$ 13,200
Business acquisition, consideration transferred		$ 40,000
Common stock investment value	$ 26,800
Collaboration Agreement | Solid Biosciences, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of common stock purchased	521,719
Maximum | Collaboration and License Agreement | Solid Biosciences, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development milestone payments	$ 25,000
Regulatory milestone payments	65,000
Commercial milestone payments	$ 165,000

License and Research Agreeme_12

License and Research Agreements - Share of Collaboration and Royalty Revenue Related to Crysvita (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	$ 560,230	$ 434,249	$ 363,329
Collaboration and Royalty | Kyowa Kirin Collaboration
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	409,524	328,054	279,394
Collaboration and Royalty | Kyowa Kirin Collaboration | Profit Share Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	248,966	231,574	215,024
Royalty revenue
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	274,815	182,652	21,692
Royalty revenue | Kyowa Kirin Collaboration | Profit Share Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	174,276	113,288	0
Product sales
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	285,415	180,413	118,927
Product sales | Kyowa Kirin Collaboration
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	134,709	75,697	42,678
Collaboration Revenue | Kyowa Kirin Collaboration | Profit Share Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	0	69,705	215,024
Non-cash royalty revenue | Kyowa Kirin Collaboration | Profit Share Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	74,690	48,581	0
Non-cash royalty revenue | Kyowa Kirin Collaboration | Royalty Revenue in European Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	$ 25,849	$ 20,783	$ 21,692

License and Research Agreeme_13

License and Research Agreements - Schedule of Cost Sharing Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cost Sharing Payments [Line Items]
Cost of sales	$ 76,728	$ 45,209	$ 28,320
Kyowa Kirin Collaboration [Member]
Cost Sharing Payments [Line Items]
Research and development	(3,670)	(6,510)	(15,974)
Selling, general and administrative	(4,082)	(17,199)	(37,217)
Cost of sales	46,027	18,476	13,250
Regeneron Pharmaceuticals Inc
Cost Sharing Payments [Line Items]
Research and development	(2,842)	7,629	7,258
Cost of sales	$ 8,030	$ 684	$ 0

License and Research Agreeme_14

License and Research Agreements - Schedule of Changes in Fair Value of Equity Investment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, Beginning balance		$ 749,239
Common stock, Purchase price of option exercise	$ 862	4,950	$ 2,552
Common stock, Ending balance	$ 713,202		749,239
Arcturus | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, Beginning balance		$ 0	18,505
Common stock, Change in fair value			(8,411)
Common stock, Sale of shares			(10,094)
Common stock, Ending balance			$ 0

License and Research Agreeme_15

License and Research Agreements - Schedule of Changes in Fair Value of Investment in Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, Beginning balance		$ 749,239
Common stock, Ending balance	$ 713,202
Common Stock | Solid Biosciences, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, Beginning balance	3,204	2,807
Common stock, Change in fair value	(1,115)	397
Common stock, Ending balance	$ 2,089	$ 3,204

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee Disclosure [Abstract]
Operating lease extension details	multiple renewal periods
Operating lease, existence of option to extend	true
Operating lease expiry term	2029
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Right-of-use lease assets	$ 25.5	$ 23.9
Cash paid for measurement of operating lease liabilities	$ 16.1	$ 13.4	$ 13.1
Operating lease weighted average remaining lease term	4 years	5 years
Operating lease weighted average discount rate	10.10%	9.60%

Leases - Summary of Components

Leases - Summary of Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lease, Cost [Abstract]
Operating lease expense	$ 11,985	$ 12,883	$ 11,775
Variable lease expense	5,893	5,272	4,785
Financing:
Amortization	0	203	343
Interest expense	0	0	37
Total	$ 17,878	$ 18,358	$ 16,940

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities and the Reconciliation of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Operating
2025	$ 13,831
2026	13,949
2027	9,019
2028	6,709
2029	5,589
Thereafter	467
Total future lease payments	49,564
Less: Amount representing interest	(9,225)
Present value of future lease payments	40,339
Less: Lease liabilities, current	$ (10,297)	$ (12,595)
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Less: Lease liabilities, current
Lease liabilities, non-current	$ 30,042	$ 30,574
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Lease liabilities, non-current

Liabilities for Sales of Futu_3

Liabilities for Sales of Future Royalties - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Jul. 31, 2022	Dec. 31, 2019	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Liability For Sale Of Future Royalties [Line Items]
Non-cash collaboration royalty revenue			$ 100,539	$ 69,364	$ 21,692
OMERS
Liability For Sale Of Future Royalties [Line Items]
Profit loss sharing percentage on net sales	30%
Royalty Purchase Agreement | RPI Finance Trust (RPI)
Liability For Sale Of Future Royalties [Line Items]
Proceeds from sale of future royalties		$ 320,000
Royalty payment termination description			The agreement with RPI will automatically terminate, and the payment of royalties to RPI will cease, in the event aggregate royalty payments received by RPI are equal to or greater than $608.0 million prior to December 31, 2030, or in the event aggregate royalty payments received by RPI are less than $608.0 million prior to December 31, 2030, or when aggregate royalty payments received by RPI are equal to $800.0 million.
Royalties transaction costs net		$ 5,800
Effective annual interest rate			6.20%
Non-cash collaboration royalty revenue			$ 99,300
Royalty Purchase Agreement | OMERS
Liability For Sale Of Future Royalties [Line Items]
Proceeds from sale of future royalties	$ 500,000
Royalty payment termination description	In July 2022, the Company entered into a Royalty Purchase Agreement with OMERS. Pursuant to the agreement, OMERS paid $500.0 million to the Company in consideration for the right to receive 30% of the future royalty payments due to the Company from KKC based on net sales of Crysvita in the U.S. and Canada under the terms of the KKC Collaboration Agreement. The calculation of royalty payments to OMERS is based on net sales of Crysvita beginning in April 2023 and will expire upon the earlier of the date on which aggregate payments received by OMERS equals $725.0 million or the date the final royalty payment is made to the Company under the KKC Collaboration Agreement.
Royalty agreement termination threshold amount	$ 725,000
Payment from sale of future royalties	500,000
Royalties transaction costs net	$ 9,100
Effective annual interest rate			7.50%
Non-cash collaboration royalty revenue			$ 123,300
Royalty Purchase Agreement | Minimum | RPI Finance Trust (RPI)
Liability For Sale Of Future Royalties [Line Items]
Royalty agreement termination threshold amount			608,000
Royalty Purchase Agreement | Maximum | RPI Finance Trust (RPI)
Liability For Sale Of Future Royalties [Line Items]
Royalty agreement termination threshold amount			$ 800,000

Liabilities for Sales of Futu_4

Liabilities for Sales of Future Royalties - Schedule of Activity Within Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Liability For Sale Of Future Royalties [Line Items]
Liability for sale of future royalties at beginning of year	$ 891,567	$ 875,439
Royalty revenue	(84,937)	(59,307)
Non-cash interest expense	63,041	75,435
Liability for sale of future royalties at end of year	869,671	891,567
RPI Finance Trust (RPI)
Liability For Sale Of Future Royalties [Line Items]
Liability for sale of future royalties at beginning of year	376,641	365,189
Royalty revenue	(25,849)	(20,783)
Non-cash interest expense	23,747	32,235
Liability for sale of future royalties at end of year	374,539	376,641
OMERS
Liability For Sale Of Future Royalties [Line Items]
Liability for sale of future royalties at beginning of year	514,926	510,250
Royalty revenue	(59,088)	(38,524)
Non-cash interest expense	39,294	43,200
Liability for sale of future royalties at end of year	$ 495,132	$ 514,926

Equity - Additional Information

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended				12 Months Ended
	Jun. 30, 2024	Feb. 29, 2024	Oct. 31, 2023	May 31, 2021	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Stockholders Equity [Line Items]
Stock sold in at-the-market offering						1,175,584
Net proceeds from at-the-market offering						$ 53.3
Pre Funded Warrant
Stockholders Equity [Line Items]
Underwritten Public Offering Shares					1,538,501	1,666,722
Number of warrants exercised					0
Common stock warrants outstanding					3,205,223	1,666,722	0
Open Market Sale
Stockholders Equity [Line Items]
Option to sell common stock aggregate offering price		$ 350		$ 350
At-the-Market Offerings
Stockholders Equity [Line Items]
Common stock shares sold					0
Underwritten Public Offering
Stockholders Equity [Line Items]
Common stock shares sold	8,782,051		9,833,334
Shares purchased by underwriters	1,346,153		1,500,000
Public offering price	$ 39		$ 30
Underwritten Public Offering | Pre Funded Warrant
Stockholders Equity [Line Items]
Underwritten Public Offering Shares	1,538,501		1,666,722
Pre-funded warrant price	$ 38.999		$ 29.999
Common stock warrants, exercise price	$ 0.001		$ 0.001
Net proceeds from sale of common stock	$ 381		$ 326.5

Equity - Summary of Pre- Funded

Equity - Summary of Pre- Funded Warrants Activity (Details) - Pre Funded Warrant - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Stockholders Equity [Line Items]
Beginning Balance	1,666,722	0
Issuance of pre-funded warrants	1,538,501	1,666,722
Ending Balance	3,205,223	1,666,722

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cash received from exercise of options	$ 5,736	$ 2,743	$ 6,242
weighted-average estimated fair value	$ 29.88	$ 25.53	$ 34.77
Total estimated fair value of options vested	$ 53,838	$ 59,663	$ 58,677
Total unrecognized compensation cost	$ 256,800
Weighted-average period to recognize cost	2 years
Stock-based compensation capitalized to inventory	$ 2,600	1,900	2,200
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total fair value of shares vested	62,500	54,600	47,100
Aggregate intrinsic value	54,000	33,000	37,800
Performance Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total fair value of shares vested	3,400	3,900	1,600
Aggregate intrinsic value	2,100	1,300	$ 2,000
Performance Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
weighted-average estimated fair value			$ 28.76
Total estimated fair value of options vested	$ 9,900	$ 3,400
Maximum | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards vesting period	4 years
Minimum | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards vesting period	1 year
2023 Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share of common stock available for grant	6,139,766
Shares available for grant, ending date	Jun. 07, 2023
2023 Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorised for issuance	10,475,837
2023 Plan and Inducement Plan | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting rights, percentage	25%
Stock based awards vesting period	4 years
2023 Plan and Inducement Plan | Maximum | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period	10 years
2023 Plan and Inducement Plan | First Anniversary | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting rights, percentage	25%
2023 Plan and Inducement Plan | Shares Vesting Monthly After First Anniversary | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting rights, percentage	2.08%
2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share of common stock available for grant	6,409,256
Shares available for grant, ending date	Jun. 07, 2033
Percentage of statutory stock awards	85%
Common stock shares issued	200,539
2014 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorised for issuance	7,330,914
Employment Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share of common stock available for grant	211,628
Shares available for grant, ending date	Feb. 03, 2031
Employment Inducement Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorised for issuance	1,200,000

Stock-Based Awards - Summary of

Stock-Based Awards - Summary of Company's Equity Plans (Details)	12 Months Ended
	Dec. 31, 2024 shares
Employment Inducement Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Year of Adoption	2021
Expiration date, as amended	Feb. 03, 2031
Shares available for future issuance	211,628
Employment Inducement Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Maximum number of shares authorized	1,200,000
2023 Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Year of Adoption	2023
Expiration date, as amended	Jun. 07, 2023
Shares available for future issuance	6,139,766
2023 Incentive Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Maximum number of shares authorized	10,475,837
2014 Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Year of Adoption	2014
Expiration date, as amended	Jun. 07, 2033
Shares available for future issuance	6,409,256
2014 Employee Stock Purchase Plan | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Maximum number of shares authorized	7,330,914

Stock-Based Awards - Summary _2

Stock-Based Awards - Summary of Company's Equity Plans (Parenthetical) (Details) - 2023 Incentive Plan	12 Months Ended
	Dec. 31, 2024 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares authorized and shares available for future issuance	1,975,837
Expiration date, as amended	Jun. 07, 2023

Stock-Based Awards - Summary _3

Stock-Based Awards - Summary of Activity Under Stock Option Plans Including 2011 Plan and 2014 Plan and 2023 Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Number of Options, Outstanding, Beginning Balance	8,787,712
Number of Options, Options granted	1,445,364
Number of Options, Options exercised	(124,536)
Number of Options, Options cancelled	(747,571)
Number of Options, Outstanding, Ending Balance	9,360,969	8,787,712
Vested and exercisable December 31, 2024	6,360,538
Vested and expected to vest December 31, 2024	9,096,200
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 67.43
Weighted Average Exercise Price, Options granted	52.91
Weighted Average Exercise Price, Options exercised	46.06
Weighted Average Exercise Price, Options cancelled	66.68
Weighted Average Exercise Price, Outstanding, Ending Balance	65.54	$ 67.43
Weighted- Average Exercise Price,Weighted Average Exercise Price	71.27
Weighted Average Exercise Price, Vested and expected to vest December 31, 2024	$ 65.95
Weighted Average Remaining Contractual Term (Years), Outstanding	6 years	6 years
Weighted Average Remaining Contractual Term (Years), Vested and exercisable - December 31, 2024	5 years
Weighted-Average Remaining Contractual Term,Vested and expected to vest December 31, 2024	6 years
Aggregate Intrinsic Value, Outstanding	$ 1,839	$ 7,558
Aggregate Intrinsic Value, Vested and exercisable - December 31, 2024	729
Aggregate Intrinsic Value, Vested and expected to vest - December 31, 2023	$ 1,742

Stock-Based Awards - Summary _4

Stock-Based Awards - Summary of the Company's options exercised and vested (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Intrinsic value of options exercised	$ 862	$ 4,950	$ 2,552
Cash received from exercise of options	$ 5,736	$ 2,743	$ 6,242
Weighted average estimated fair value of options granted	$ 29.88	$ 25.53	$ 34.77
Estimated fair value of options vested	$ 53,838	$ 59,663	$ 58,677

Stock-Based Awards- Summary Act

Stock-Based Awards- Summary Activity Under the Performance Stock Option (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vested and exercisable December 31, 2024	6,360,538
Vested and expected to vest December 31, 2024	9,096,200
Weighted- Average Exercise Price,Weighted Average Exercise Price	$ 71.27
Weighted Average Exercise Price, Vested and expected to vest December 31, 2024	$ 65.95
Weighted-Average Remaining Contractual Term,Vested and expected to vest December 31, 2024	6 years
Weighted Average Remaining Contractual Term (Years), Vested and exercisable - December 31, 2024	5 years
Aggregate Intrinsic Value, Vested and exercisable - December 31, 2024	$ 729
Aggregate Intrinsic Value, Vested and expected to vest - December 31, 2023	$ 1,742
Performance Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Outstanding, Number of Shares, Unvested, Beginning Balance	1,380,998
PSOs cancelled	(135,707)
Outstanding, Number of Shares, Unvested, Ending Balance	1,245,291	1,380,998
Vested and exercisable December 31, 2024	422,594
Vested and expected to vest December 31, 2024	930,420
Outstanding, Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance	$ 67.37
Weighted Average Exercise Price ,PSOs cancelled	67.37
Weighted- Average Exercise Price,Outstanding December 31, 2023	67.37	$ 67.37
Weighted- Average Exercise Price,Weighted Average Exercise Price	67.37
Weighted Average Exercise Price, Vested and expected to vest December 31, 2024	$ 67.37
Weighted-Average Remaining Contractual Term,Outstanding at December 31, 2023	2 years	3 years
Weighted-Average Remaining Contractual Term,Vested and expected to vest December 31, 2024	2 years
Weighted Average Remaining Contractual Term (Years), Vested and exercisable - December 31, 2024	2 years
Aggregate Intrinsic Value, Outstanding	$ 0	$ 0
Aggregate Intrinsic Value, Vested and exercisable - December 31, 2024	0
Aggregate Intrinsic Value, Vested and expected to vest - December 31, 2023	$ 0

Stock-Based Awards - Summary _5

Stock-Based Awards - Summary of Activity Under Restricted Stock Units (RSUs) from 2014 Plan (Details) - Restricted Stock Units	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Number of Shares, Unvested, Beginning Balance | shares	3,444,112
Number of shares, granted | shares	3,169,688
Number of shares, vested | shares	(1,043,199)
Number of shares, cancelled | shares	(400,654)
Outstanding, Number of Shares, Unvested, Ending Balance | shares	5,169,947
Outstanding, Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance | $ / shares	$ 55.21
Weighted-Average Grant Date Fair Value, granted | $ / shares	53.06
Weighted-Average Grant Date Fair Value, vested | $ / shares	59.92
Weighted-Average Grant Date Fair Value, cancelled | $ / shares	54.13
Weighted- Average Exercise Price,Outstanding December 31, 2023 | $ / shares	$ 53.22

Stock-Based Awards - Summary _6

Stock-Based Awards - Summary of Activity Under PSUs from 2014 Plan (Details) - Performance Stock Units	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Number of Shares, Unvested, Beginning Balance | shares	506,106
Number of shares, granted | shares	274,484
Number of shares, vested | shares	(47,464)
Number of shares, cancelled | shares	(114,944)
Outstanding, Number of Shares, Unvested, Ending Balance | shares	618,182
Outstanding, Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance | $ / shares	$ 60.82
Weighted-Average Grant Date Fair Value, granted | $ / shares	62.6
Weighted-Average Grant Date Fair Value, vested | $ / shares	72.17
Weighted-Average Grant Date Fair Value, cancelled | $ / shares	68.07
Weighted- Average Exercise Price,Outstanding December 31, 2023 | $ / shares	$ 59.39

Stock-Based Awards - Summary _7

Stock-Based Awards - Summary of Stock-Based Compensation Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 158,056	$ 135,213	$ 130,368
Cost of sales
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,469	1,166	902
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	86,616	74,531	74,464
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 69,971	$ 59,516	$ 55,002

Stock-Based Awards - Fair Value

Stock-Based Awards - Fair Value of Stock Option Awards Granted Estimated Using Black-Scholes Option-Pricing Model (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term in years	6 years	6 years	6 years
Expected volatility	55%	55%	56%
Risk-free interest rate	4.20%	4.20%	2%
Expected dividend rate	0%	0%	0%
Granted [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term in years			4 years
Expected volatility			57%
Risk-free interest rate			1.50%
Expected dividend rate			0%

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Contribution Pension And Other Post Retirement Plan Disclosure [Abstract]
Contribution expenses	$ 9.8	$ 9.7	$ 9

Income Taxes - Components of Co

Income Taxes - Components of Company's Loss Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Domestic	$ 564,072	$ 608,166	$ 703,411
Foreign	3,514	298	(1,686)
Total loss before income taxes	$ 567,586	$ 608,464	$ 701,725

Income Taxes - Components of _2

Income Taxes - Components of Company's Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Current provision for income taxes:
State	$ 224	$ (3,187)	$ 6,062
International	2,745	3,127	1,274
Total current tax provision	2,969	(60)	7,336
Deferred tax provision:
State		(1,608)	(1,640)
International	(1,372)	(157)
Total deferred tax provision	(1,372)	(1,765)	(1,640)
Total (benefit from) provision for income taxes	$ 1,597	$ (1,825)	$ 5,696

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2012
Tax Credit Carryforward [Line Items]
Current state income tax expense	$ 2,969	$ (60)	$ 7,336
Deferred tax assets net operating loss, federal tax credits				$ 200
Deferred tax assets net operating loss carryforwards	309,301	266,253
Valuation allowance increased	170,700	141,300
Effective income tax rate unrecognized tax benefits	1,300
Recognized accrued interest and penalties	100	200	0
Undistributed earnings of foreign subsidiaries	13,000
Federal
Tax Credit Carryforward [Line Items]
Deferred tax assets operating loss carryforwards subject to expiration	$ 1,190,500	1,004,800
Operating loss carryforwards expiration year	2031
Tax credit carryforwards	$ 45,100	46,900
Tax credit carryforwards expiration year	2031
Deferred tax assets net operating loss carryforwards				3,600
Federal | Orphan Drug Credits [Member]
Tax Credit Carryforward [Line Items]
Deferred tax assets operating loss carryforwards subject to expiration	$ 338,500	269,600
Operating loss carryforwards expiration year	2031
State
Tax Credit Carryforward [Line Items]
Current state income tax expense	$ 200	4,800	$ 6,100
Deferred tax assets operating loss carryforwards subject to expiration	$ 744,400	659,900
Operating loss carryforwards expiration year	2031
Tax credit carryforwards	$ 92,000	74,400
Deferred tax assets net operating loss carryforwards				$ 3,600
International
Tax Credit Carryforward [Line Items]
Current state income tax expense	$ 1,400	$ 3,000

Income Taxes - Effective Tax Ra

Income Taxes - Effective Tax Rate of Provision for Income Taxes from Federal Statutory Rate (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory income tax rate	21%	21%	21%
State income taxes, net of federal benefit		0.80%	(0.40%)
Federal tax credits	10.80%	7.30%	5.90%
Other	0.10%	(0.70%)	(0.10%)
Nondeductible permanent items	(1.10%)	(0.30%)	(0.60%)
Stock-based compensation	(1.60%)	(1.80%)	(1.20%)
Uncertain tax positions	(2.00%)	(1.40%)	(1.20%)
Change in valuation allowance	(27.10%)	(24.10%)	(24.00%)
Foreign rate differential	(0.40%)	(0.50%)	(0.20%)
Provision for income taxes	(0.30%)	0.30%	(0.80%)

Income Taxes - Schedule of Tax

Income Taxes - Schedule of Tax Effect of Temporary Differences to Significant Portions of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Loss carryforwards	$ 309,301	$ 266,253
Tax credits	369,988	305,198
Stock options	51,939	44,795
Accruals and reserves	32,140	27,694
Fixed assets and intangibles	32,391	33,853
Liabilities for sales of future royalties	196,664	205,400
Basis difference in equity investments	8,683	8,423
Capitalized research and development costs	211,969	149,898
Other	589	281
Gross deferred tax assets	1,213,664	1,041,795
Valuation allowance	(1,206,514)	(1,035,836)
Total deferred tax assets	7,150	5,959
Deferred tax liabilities:
Gross deferred tax liabilities	(35,836)	(36,017)
Net deferred tax liabilities	(28,686)	(30,058)
Right-of-use Lease Assets
Deferred tax liabilities:
Gross deferred tax liabilities	(5,778)	(5,329)
In-process Research and Development [Member]
Deferred tax liabilities:
Gross deferred tax liabilities	$ (30,058)	$ (30,688)

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 79,998	$ 66,794	$ 55,360
Additions based on tax positions related to current year	14,825	12,562	11,316
Additions for tax positions of prior years	2,173	642	377
Reductions for tax positions of prior years	0	0	(259)
Balance at end of year	$ 96,996	$ 79,998	$ 66,794

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2024
Manufacturing and Services
Commitments And Contingencies Disclosure Line Items
Contractual Obligation Maturity Period	12 months

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Aggregate Payments under Contractually Binding Manufacturing and Service Agreements (Details) - Manufacturing and Services $ in Thousands	Dec. 31, 2024 USD ($)
Commitments And Contingencies Disclosure Line Items
2025	$ 33,842
2026	9,145
Contractual Obligation, Total	$ 42,987

Related Party Transaction - Add

Related Party Transaction - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Total Contract Value	$ 1,000
Contribution period	4 years
Research and development		$ 697,865	$ 648,449	$ 705,789
Non Profit Foundation [Member]
Related Party Transaction [Line Items]
Research and development		$ 300	$ 300	$ 300

Net Loss per Share - Computatio

Net Loss per Share - Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (569,183)	$ (606,639)	$ (707,421)
Denominator:
Weighted-average shares used to computing net loss per share, basic	90,538,118	73,543,862	69,914,225
Weighted-average shares used to computing net loss per share, diluted	90,538,118	73,543,862	69,914,225
Net loss per share, basic	$ (6.29)	$ (8.25)	$ (10.12)
Net loss per share, diluted	$ (6.29)	$ (8.25)	$ (10.12)

Net Loss per Share - Outstandin

Net Loss per Share - Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	16,292,260	14,160,736	11,298,516
Options to Purchase Common Stock, RSUs, and PSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	16,284,470	14,152,286	11,290,935
Employee Stock Purchase Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	7,790	8,450	7,581

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Schedule of Total Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Cumulative foreign currency translation adjustment	$ (1,650)	$ (606)
Unrealized gain (loss) on securities available-for-sale	1,007	1,253
Total accumulated other comprehensive (loss) income	$ (643)	$ 647