Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2025
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited Consolidated Financial Statements have been prepared in accordance with the U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10-01 of Regulation S-X. Accordingly, certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but that is not required for interim reporting purposes, has been omitted. In the opinion of management, the accompanying unaudited Consolidated Financial Statements reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company's interim financial information. Management has determined that the Company operates in one segment focused on discovering, developing, and delivering novel medicines for rare diseases. The accompanying unaudited Consolidated Financial Statements and related notes should be read in conjunction with the Company's financial statements and related notes as contained in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2024. For a complete description of the Company's accounting policies, please refer to the Annual Report on Form 10-K for the fiscal year ended December 31, 2024.
Consolidation	Consolidation The Consolidated Financial Statements include the accounts of the Company and its subsidiaries. Intercompany accounts and transactions are eliminated in consolidation.
Foreign Currency Transactions	Foreign Currency Transactions The functional currency for most of the Company's foreign subsidiaries is their local currency. For non-U.S. subsidiaries that transact in a functional currency other than the U.S. dollar, assets and liabilities are translated at current rates of exchange at the balance sheet date. Income and expense items are translated at the weighted average foreign exchange rates for the period. Adjustments resulting from the translation of the financial statements of the Company's foreign operations into U.S. dollars are excluded from the determination of net income and are recorded in accumulated other comprehensive income, a separate component of stockholders' equity. Transactions which are not in the functional currency of the entity are remeasured into the functional currency with gains or losses resulting from the remeasurement recorded in other (expense) income.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.
Cash, Cash Equivalents, Marketable Securities, and Restricted Cash	Cash, Cash Equivalents, Marketable Securities, and Restricted Cash The Company considers all highly liquid investments purchased with a maturity of three months or less at the date of acquisition to be cash equivalents. Marketable securities consist of fixed income investments with a maturity of greater than three months and other highly liquid investments that can be readily purchased or sold using established markets. These investments are classified as available-for-sale and are reported at fair value on the Company's Consolidated Balance Sheets. Unrealized holding gains and losses are reported within other comprehensive income (loss) in the Company's Consolidated Statements of Comprehensive Loss. Fair value is based on available market information including quoted market prices, broker or dealer quotations, or other observable inputs. The cost of securities sold is based on the specific identification method. Restricted cash consists primarily of funds held to satisfy the requirements of certain agreements that are restricted in their use and is included as a component of other non-current assets on the Company's Consolidated Balance Sheets.
Concentration of Credit Risk	Concentration of Credit Risk The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash, cash equivalents, and marketable securities. The Company maintains its cash and cash equivalents in bank accounts, which, at times, exceed federally insured limits. The Company invests its marketable securities in high-quality commercial financial instruments. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents, or marketable securities. The Company is subject to credit risk from its accounts receivable primarily related to its product sales of Galafold® and Pombiliti® + Opfolda®. The Company's accounts receivable at June 30, 2025 have arisen from product sales primarily in Europe, the U.S., and Japan. The Company will periodically assess the financial strength of its customers to establish allowances for anticipated losses, if any.
Revenue Recognition	Revenue Recognition The Company has recorded revenue on sales where its products are available either on a commercial basis or through a reimbursed early access program. Product orders are generally received from distributors and pharmacies. The Company recognizes revenue when its performance obligations to its customers have been satisfied, which occurs at a point in time when the pharmacies or distributors obtain control of the products. The transaction price is determined based on fixed consideration in the Company's customer contracts and is recorded net of estimates for variable consideration, which primarily consist of third-party discounts and rebates. The identified variable consideration is recorded as a reduction of revenue at the time revenue from the sale is recognized. The Company recognizes revenue to the extent that it is probable that a significant revenue reversal will not occur in a future period. These estimates may differ from actual consideration received. The Company evaluates these estimates each reporting period to reflect known changes.
Inventories and Cost of Goods Sold	Inventories and Cost of Goods Sold Until regulatory approval of Pombiliti® + Opfolda®, the Company expensed all manufacturing costs as research and development expense. Upon regulatory approval, the Company began capitalizing costs related to the purchase and manufacture of Pombiliti® + Opfolda®. Inventories are stated at the lower of cost and net realizable value, determined by the first-in, first-out method. Inventories are reviewed periodically to identify slow-moving or obsolete inventory based on projected sales activity as well as product shelf-life. In evaluating the recoverability of inventories produced, the probability that revenue will be obtained from the future sale of the related inventory is considered and inventory value is written down for inventory quantities in excess of expected requirements. Expired inventory is disposed of and the related costs are recognized as cost of goods sold in the Company's Consolidated Statements of Operations. Cost of goods sold includes the cost of inventory sold, manufacturing and supply chain costs, product shipping and handling costs, provisions for excess and obsolete inventory, as well as royalties payable. A portion of inventory available for sale was expensed as research and development costs prior to regulatory approval and as such, the cost of goods sold and related gross margins are not necessarily indicative of future costs of goods sold and gross margin.
Segment Information	Segment Information The Company currently operates in one business segment focused on discovering, developing, and delivering novel medicines for rare diseases. The Company is not organized by market and is managed and operated as one business. A single management team reports to the chief operating decision maker ("CODM"), its Chief Executive Officer, who comprehensively manages the entire business. The Company and its CODM evaluate performance and allocate resources primarily based on Net product sales and Net loss within the Consolidated Statement of Operations that is regularly provided. Net loss is used to monitor budget to actual results and actuals against prior periods. The Company does not accumulate discrete financial information with respect to separate service lines, and thus there is one reportable segment. The Company does not operate any separate lines of business or separate business entities with respect to its products. Accordingly, the Consolidated Statements of Operations and Consolidated Balance Sheets provide information regarding significant segment expenses and segment assets. Revenue segregation by product line is presented in the revenue recognition section earlier in this footnote.
Recent Accounting Developments	Recent Accounting Developments - Guidance Adopted in 2025 In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The ASU requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, must be applied prospectively with an option to apply retrospectively, and early adoption is permitted. The Company adopted this guidance on January 1, 2025. This ASU applies to disclosure requirements only, and the Company will provide required annual disclosures as part of the 2025 Annual Report on Form 10-K. The adoption of this guidance is not expected to have a significant impact on the Company's consolidated financial statements. Recent Accounting Developments - Guidance Not Yet Adopted 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." The standard is intended to require more detailed disclosures about specified categories of expenses (including employee compensation, depreciation, and amortization) included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments may be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this standard will have on its consolidated financial statements. On July 4, 2025, the U.S. enacted the budget reconciliation bill, H.R. 1, also referred to as, the One Big Beautiful Bill Act of 2025 (“OBBBA”). The OBBBA contains several changes to corporate taxation including modifications to capitalization of research and development expenses, limitations on deductions for interest expense and accelerated fixed asset depreciation. The legislation has multiple effective dates, with certain provisions effective in 2025 and others implemented through 2027. The changes resulting from the tax provisions in OBBBA are not expected to have a material impact on the Company’s results of operations.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2025

The accompanying unaudited Consolidated Financial Statements have been prepared in accordance with the U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10-01 of Regulation S-X. Accordingly, certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but that is not required for interim reporting purposes, has been omitted. In the opinion of management, the accompanying unaudited Consolidated Financial Statements reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company's interim financial information. Management has determined that the Company operates in one segment focused on discovering, developing, and delivering novel medicines for rare diseases.

The accompanying unaudited Consolidated Financial Statements and related notes should be read in conjunction with the Company's financial statements and related notes as contained in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2024. For a complete description of the Company's accounting policies, please refer to the Annual Report on Form 10-K for the fiscal year ended December 31, 2024.

Consolidation

The Consolidated Financial Statements include the accounts of the Company and its subsidiaries. Intercompany accounts and transactions are eliminated in consolidation.

Foreign Currency Transactions

The functional currency for most of the Company's foreign subsidiaries is their local currency. For non-U.S. subsidiaries that transact in a functional currency other than the U.S. dollar, assets and liabilities are translated at current rates of exchange at the balance sheet date. Income and expense items are translated at the weighted average foreign exchange rates for the period. Adjustments resulting from the translation of the financial statements of the Company's foreign operations into U.S. dollars are excluded from the determination of net income and are recorded in accumulated other comprehensive income, a separate component of stockholders' equity. Transactions which are not in the functional currency of the entity are remeasured into the functional currency with gains or losses resulting from the remeasurement recorded in other (expense) income.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.

Cash, Cash Equivalents, Marketable Securities, and Restricted Cash

The Company considers all highly liquid investments purchased with a maturity of three months or less at the date of acquisition to be cash equivalents. Marketable securities consist of fixed income investments with a maturity of greater than three months and other highly liquid investments that can be readily purchased or sold using established markets. These investments are classified as available-for-sale and are reported at fair value on the Company's Consolidated Balance Sheets. Unrealized holding gains and losses are reported within other comprehensive income (loss) in the Company's Consolidated Statements of Comprehensive Loss. Fair value is based on available market information including quoted market prices, broker or dealer quotations, or other observable inputs. The cost of securities sold is based on the specific identification method.

Restricted cash consists primarily of funds held to satisfy the requirements of certain agreements that are restricted in their use and is included as a component of other non-current assets on the Company's Consolidated Balance Sheets.

Concentration of Credit Risk

The Company's financial instruments that are exposed to concentration of credit risk consist primarily of cash, cash equivalents, and marketable securities.

The Company maintains its cash and cash equivalents in bank accounts, which, at times, exceed federally insured limits. The Company invests its marketable securities in high-quality commercial financial instruments. The Company has not recognized any losses from credit risks on such accounts during any of the periods presented. The Company believes it is not exposed to significant credit risk on its cash, cash equivalents, or marketable securities.

The Company is subject to credit risk from its accounts receivable primarily related to its product sales of Galafold® and Pombiliti® + Opfolda®. The Company's accounts receivable at June 30, 2025 have arisen from product sales primarily in Europe, the U.S., and Japan. The Company will periodically assess the financial strength of its customers to establish allowances for anticipated losses, if any.

Revenue Recognition

The Company has recorded revenue on sales where its products are available either on a commercial basis or through a reimbursed early access program. Product orders are generally received from distributors and pharmacies.

The Company recognizes revenue when its performance obligations to its customers have been satisfied, which occurs at a point in time when the pharmacies or distributors obtain control of the products. The transaction price is determined based on fixed consideration in the Company's customer contracts and is recorded net of estimates for variable consideration, which primarily consist of third-party discounts and rebates. The identified variable consideration is recorded as a reduction of revenue at the time revenue from the sale is recognized. The Company recognizes revenue to the extent that it is probable that a significant revenue reversal will not occur in a future period. These estimates may differ from actual consideration received. The Company evaluates these estimates each reporting period to reflect known changes.

Inventories and Cost of Goods Sold

Until regulatory approval of Pombiliti® + Opfolda®, the Company expensed all manufacturing costs as research and development expense. Upon regulatory approval, the Company began capitalizing costs related to the purchase and manufacture of Pombiliti® + Opfolda®.

Inventories are stated at the lower of cost and net realizable value, determined by the first-in, first-out method. Inventories are reviewed periodically to identify slow-moving or obsolete inventory based on projected sales activity as well as product shelf-life. In evaluating the recoverability of inventories produced, the probability that revenue will be obtained from the future sale of the related inventory is considered and inventory value is written down for inventory quantities in excess of expected requirements. Expired inventory is disposed of and the related costs are recognized as cost of goods sold in the Company's Consolidated Statements of Operations.

Cost of goods sold includes the cost of inventory sold, manufacturing and supply chain costs, product shipping and handling costs, provisions for excess and obsolete inventory, as well as royalties payable. A portion of inventory available for sale was expensed as research and development costs prior to regulatory approval and as such, the cost of goods sold and related gross margins are not necessarily indicative of future costs of goods sold and gross margin.

Segment Information

The Company currently operates in one business segment focused on discovering, developing, and delivering novel medicines for rare diseases. The Company is not organized by market and is managed and operated as one business. A single management team reports to the chief operating decision maker ("CODM"), its Chief Executive Officer, who comprehensively manages the entire business. The Company and its CODM evaluate performance and allocate resources primarily based on Net product sales and Net loss within the Consolidated Statement of Operations that is regularly provided. Net loss is used to monitor budget to actual results and actuals against prior periods. The Company does not accumulate discrete financial information with respect to separate service lines, and thus there is one reportable segment. The Company does not operate any separate lines of business or separate business entities with respect to its products. Accordingly, the Consolidated Statements of Operations and Consolidated Balance Sheets provide information regarding significant segment expenses and segment assets. Revenue segregation by product line is presented in the revenue recognition section earlier in this footnote.

Recent Accounting Developments

Recent Accounting Developments - Guidance Adopted in 2025

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The ASU requires disclosure of disaggregated income taxes paid, prescribes standard categories for the components of the effective tax rate reconciliation, and modifies other income tax-related disclosures. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, must be applied prospectively with an option to apply retrospectively, and early adoption is permitted. The Company adopted this guidance on January 1, 2025. This ASU applies to disclosure requirements only, and the Company will provide required annual disclosures as part of the 2025 Annual Report on Form 10-K. The adoption of this guidance is not expected to have a significant impact on the Company's consolidated financial statements.

Recent Accounting Developments - Guidance Not Yet Adopted

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." The standard is intended to require more detailed disclosures about specified categories of expenses (including employee compensation, depreciation, and amortization) included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments may be applied either prospectively to financial statements issued for reporting periods after the effective date of this ASU or retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this standard will have on its consolidated financial statements.

On July 4, 2025, the U.S. enacted the budget reconciliation bill, H.R. 1, also referred to as, the One Big Beautiful Bill Act of 2025 (“OBBBA”). The OBBBA contains several changes to corporate taxation including modifications to capitalization of research and development expenses, limitations on deductions for interest expense and accelerated fixed asset depreciation. The legislation has multiple effective dates, with certain provisions effective in 2025 and others implemented through 2027. The changes resulting from the tax provisions in OBBBA are not expected to have a material impact on the Company’s results of operations.