Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2025
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements include those of the Company and its subsidiaries, MoonLake Immunotherapeutics AG, a Swiss stock corporation (Aktiengesellschaft) registered with the commercial register of the Canton of Zug, Switzerland under the number CHE-433.093.536 ("MoonLake AG"), MoonLake Immunotherapeutics Ltd., a private limited company incorporated in the United Kingdom, and MNLK Immunotherapeutics, Unipessoal Lda, a private limited company incorporated in Portugal, after elimination of all intercompany accounts and transactions. The accompanying unaudited condensed consolidated financial statements and notes hereto have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) as set forth by the Financial Accounting Standards Board (“FASB”) and in conformity with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X for interim financial reporting. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the FASB. In the opinion of management, all material adjustments necessary for a fair presentation of the financial information, which are of a normal and recurring nature, have been made for the interim periods reported. Results of operations for the three months ended March 31, 2025 are not necessarily indicative of the results for the entire fiscal year or any other period. The unaudited condensed consolidated financial information for the three months ended March 31, 2025 and 2024 have been prepared on the same basis as and should be read in conjunction with MoonLake’s audited financial statements and notes thereto for the year ended December 31, 2024 included in the Annual Report. In the current year, the Company has changed its presentation from ones to thousands and, as a result, rounding adjustments have been made to amounts disclosed in prior years. The presentation currency of MoonLake is the U.S. Dollar (“$”) and all amounts are presented as such, unless otherwise indicated. The term “Swiss franc” and “CHF” refer to the legal currency of Switzerland, "GBP" refers to the legal currency of the United Kingdom, and “€” and "Euro" refer to the legal currency of Portugal.
Use of Estimates	The preparation of financial statements in conformity with U.S. GAAP requires the Company to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of expenses. The significant judgments, estimates and assumptions relevant to the Company relate to: •determining whether a transaction should be accounted for as a business combination or an asset acquisition; •determining whether the in-process research and development expenditure (“IPR&D”) has an alternative future use; •determining assumptions used in estimating the fair value of share-based compensation; •estimating the recoverability of the deferred tax asset; and •estimating the amount of accruals in connection with the completion of clinical trial milestones. The Company bases its judgments and estimates on various factors and information, which may include, but are not limited to, the Company’s forecasts and future plans, current economic conditions and observable market-based transactions of its own shares, the results of which form the basis for making judgments about the carrying value of assets and liabilities and recorded amounts of expenses that are not readily apparent from other sources. To the extent there are material differences between the Company’s estimates and the actual results, the Company’s future results of operation may be affected.
Segment Information	The Company operates as a single operating segment. The Company’s chief operating decision maker (“CODM”), its Chief Executive Officer, manages the Company’s operations on a stand-alone basis for the purposes of allocating resources and assessing financial performance.
Cash and Cash Equivalents	The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents are recorded at cost, which approximates fair value.
Marketable Securities and Short-Term Investments	The Company invests in short-term marketable securities in the form of debt securities. At the time of purchase, the Company assesses whether such debt security should be classified as held-to-maturity or available-for-sale debt securities. Debt securities are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Held-to-maturity debt securities are carried at amortized cost, adjusted for accretion of discounts or amortization of premiums to maturity computed under the effective interest method. Such accretion or amortization is included in “other income, net”. Marketable debt securities not classified as held-to-maturity are classified as available-for-sale and reported at fair value. Net unrealized gains and losses on available-for-sale debt securities are excluded from the determination of earnings and are instead recognized in the “Accumulated other comprehensive income” component of shareholders’ equity until realized. Realized gains and losses on available-for-sale debt securities are computed based upon the historical cost of these securities, using the specific identification method. Interest income is recognized when earned. Realized gains and losses are included in "other income, net" and the cost of securities sold is determined using the specific-identification method. Marketable debt securities are classified as either “Cash and cash equivalents” or “Short‑term marketable debt securities” according to their original maturity at the time of acquisition. Changes in unrealized gains and losses pertaining to cash equivalent securities are added back into the consolidated statements of cash flows as those are excluded from the determination of earnings but impact the cash and cash equivalents position. The Company estimates credit losses expected over the life of financial assets based on historical experience, current conditions and reasonable and supportable forecasts. There is no material impact to the consolidated financial statements given the investments are highly liquid thereby carrying negligible credit loss risk and are all held with reputable companies with a low risk of default.
Concentration of Credit Risk	Financial instruments that potentially subject the Company to concentration of credit risk consist of cash accounts in large financial institutions which, at times, may exceed the CHF 100 thousand deposit protection limit in Switzerland, the $250 thousand Federal Deposit Insurance Corporation deposit insurance coverage limit in the United States, the GBP 85 thousand Financial Services Compensation Scheme deposit protection limit in the United Kingdom, or the €100 thousand Fundo de Garantia de Depósitos deposit protection limit in Portugal. The Company believes it is not exposed to significant credit risk due to the financial strength of the depository institutions in which the cash and cash equivalents are held. Additionally, the Company ensures further protection against credit risk by diversifying its cash holdings across a variety of credit institutions, thereby minimizing the potential impact of any adverse events on a single institution. Further, the Company's investment strategy for cash (in excess of current business requirements) is set to invest in short-term marketable debt securities. Management actively monitors credit risk in the investment portfolio. Credit risk exposures are controlled in accordance with policies approved by the board of directors to identify, measure, monitor and control credit risks.
Fair Value Measurements	The Company follows the guidance included in ASC 820, Fair Value Measurement. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There are three levels of inputs to fair value measurements: •Level 1, meaning the use of quoted prices for identical instruments in active markets; •Level 2, meaning the use of quoted prices for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable; and •Level 3, meaning the use of unobservable inputs. Observable market data is used when available. Transfers between Levels 1, 2 or 3 within the fair value hierarchy are recognized at the end of the reporting period when the respective transaction occurred.
Long-Term Debt	Long-term debt is recognized as the amount of cash proceeds received, net of debt issuance cost incurred. It is subsequently reported at amortized cost. Interest expense is calculated using the effective interest method and any difference between the proceeds (net of debt issuance cost) and the principal amount is recognized through interest expense over the estimated life of the related debt.
Leases	The Company determines if an arrangement is or contains a lease at contract inception. For these arrangements, it is evaluated if the arrangement involves an identified asset that is physically distinct or whether the Company has the right to substantially all of the capacity of an identified asset that is not physically distinct. In arrangements that involve an identified asset, there is also judgment in evaluating if the Company has the right to direct the use of that asset. MoonLake does not have any finance leases. As of March 31, 2025, the Company has five operating leases related to the office spaces located in (i) Dorfstrasse 29, 6300, Zug, Switzerland (comprised of two leases), (ii) 95 Regent Street, CB2 1AW, Cambridge, England, United Kingdom, and (iii) Rua Manuel Pinto de Azedevo 860, 4150-335, Porto, Portugal (comprised of two leases). The operating leases are recognized on a straight-line basis over the lease term commencing on the date the Company has the right to use the leased property. Right-of-use assets and lease liabilities are measured at the lease commencement date based on the present value of the remaining lease payments over the lease term, determined using the discount rate for the lease at the commencement date. Because the rate implicit in the leases is not readily determinable, the Company uses the incremental borrowing rate as the discount rate, which approximates the interest rate at which the Company could borrow on a collateralized basis with similar terms and payments and in similar economic environments. Leases with an initial term of 12 months or less that do not have the option to purchase the underlying asset are not recorded on the balance sheet, with lease expense for these leases recognized on a straight-line basis over the lease term commencing on the date the Company has the right to use the leased property.
Property and Equipment	Property and equipment, net is stated at cost, net of accumulated depreciation. Depreciation is computed using the straight-line method based on the estimated useful lives of three to five years. As of March 31, 2025, property and equipment, net relates to information technology, office equipment, and leasehold improvements.
Impairment of Long-Lived Assets	The Company reviews all long-lived assets, which consist of operating lease right-of-use assets, and property and equipment, whenever events or changes in circumstance indicate that these assets may not be recoverable. When evaluating long-lived assets, if the Company concludes that the estimated undiscounted cash flows attributable to the assets are less than their carrying value, the Company recognizes an impairment loss based on the excess of the carrying amount of the assets over their respective fair values.
Research and Development Contract Costs and Accruals	Research and development expenses include employee payroll, consulting, contract research and contract manufacturing costs attributable to research and development activities and are expensed as incurred. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development expenses in the period in which it is probable that a liability has been incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed. The Company has entered into various research and development contracts with companies both inside and outside of the United States. These agreements are generally cancellable, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.
Share-Based Compensation	Share-Based Compensation The Company recognizes compensation expense based on estimated fair values for all stock-based payment awards made to eligible employees, members of the board of directors and independent contractors that are expected to vest. The valuation of stock option awards is determined at the date of grant using the Black-Scholes option pricing model. The Black-Scholes option pricing model requires the Company to make assumptions and judgements about the inputs used in the calculations, such as the fair value of the common stock, expected term, expected volatility of the Company’s common stock, risk-free interest rate and expected dividend yield. The valuation of restricted stock awards is measured by the fair value of the Company’s common stock on the date of the grant. For all stock options granted, the Company calculated the expected term as the period that share-based awards are expected to be outstanding. The estimate of expected volatility is based on comparative companies’ volatility within the Company's industry. The risk-free rate is based on the yield available on United States Treasury zero-coupon issues corresponding to the expected term of the award. The fair value of the common stock granted under the ESPP (as defined in Note 14 — Share-Based Compensation) was historically estimated by management with reference to the market-based transaction with its Series A investors, as there was no public market for the common stock. Share-based payment arrangements are accounted for under the fair value method. Total compensation is measured at grant date, based on the fair value of the award at that date, and recorded in earnings over the period the employees are required to render service. The Company recognizes compensation cost only for those awards expected to meet the service conditions on a straight-line basis over the requisite service period of the award.
Foreign Currency	The functional currency of the Company and its subsidiaries is the U.S. dollar. Balances and transactions denominated in foreign currencies are converted as follows: monetary assets and liabilities are translated using exchange rates in effect at the balance sheet dates and non-monetary assets and liabilities are translated at historical exchange rates. Income and expenses are translated at the daily exchange rate on the respective transaction date. Gains or losses from foreign currency translation are included in the consolidated statements of operations and comprehensive loss in "other income, net".
Income Taxes	The Company accounts for income taxes by using the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is recorded to the extent it is more likely than not that all or a portion of the Company's deferred tax assets will not be realized. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date.
Net Loss per Class A Ordinary Shares	Basic net loss per Class A Ordinary Share is calculated using the two-class method under which earnings are allocated to both Class A Ordinary Shares and participating securities. Basic net loss per share is calculated by dividing the net loss attributable to Class A Ordinary Shares by the weighted-average number of Class A Ordinary Shares outstanding for the period. The diluted net loss per Class A Ordinary Share is computed by dividing the net loss using the weighted-average number of Class A Ordinary Shares and, if dilutive, potential Class A Ordinary Shares outstanding during the period. In periods in which the Company reports a net loss attributable to shareholders of Class A Ordinary Shares, diluted net loss per share attributable to shareholders of Class A Ordinary Shares is the same as basic net loss per share attributable to shareholders of Class A Ordinary Shares, since dilutive Class A Ordinary Shares are not assumed to be outstanding if their effect is anti-dilutive.
Acquisitions	The Company evaluates acquisitions of assets and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first assessing whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. On April 29, 2021, MoonLake AG entered into an in-licensing agreement (the “In-License Agreement”) with Merck Healthcare KGaA, Darmstadt, Germany (“MHKDG”) to acquire the Sonelokimab program (the “SLK Program”) and determined that substantially all of the fair value of the gross assets acquired related to IPR&D of SLK. Therefore, this transaction was accounted for as an asset acquisition. IPR&D represents incomplete technologies that the Company acquires, which at the time of acquisition, are still under development and have no alternative future use. The fair value of such technologies is expensed upon acquisition. A technology is considered to have an alternative future use if it is probable that the Company will use the asset in its current, incomplete state as it existed at the acquisition date, in another research and development project that has not yet commenced, and economic benefit is anticipated from that use. If a technology is determined to have an alternative future use, then the fair value of the program would be recorded as an asset on the balance sheet rather than expensed. Contingent consideration payments (for example milestone payments due upon the occurrence of a specific event) in asset acquisitions are recognized in the period in which it is probable that a liability has been incurred (unless the contingent consideration meets the definition of a derivative, in which case the amount becomes part of the cost in the asset acquired). Upon recognition of the contingent consideration payment, the amount is expensed if it relates to IPR&D or capitalized if it relates to a developed product which is generally considered to be when clinical trials have been completed and regulatory approval obtained. Future royalty payments due on net sales will be recognized in cost of goods sold when net sales are recognized.
Pension	The Company accounts for pension assets and liabilities in accordance with ASC 715, Compensation – Retirement Benefits, which requires the recognition of the funded status of pension plans in the Company’s consolidated balance sheet. The liability in respect to defined benefit pension plans is the projected benefit obligation calculated annually by independent actuaries using the projected unit credit method. The projected benefit obligation as of March 31, 2025 represents the actuarial present value of the estimated future payments required to settle the obligation that is attributable to employee services rendered before that date. Service costs for such pension plans, represented in the net periodic pension benefit cost, are included in the personnel expenses of the various functions where the employees are engaged. The other components of net benefit cost are included in the consolidated statements of operations and comprehensive loss separately from the service cost component, in “other income, net.” Plan assets are recorded at their fair value. Gains or losses arising from plan curtailments or settlements are accounted for at the time they occur. Any net pension asset is limited to the present value of the future economic benefits available to the Company in the form of refunds from the plan or expected reductions in future contributions to the plan. Actuarial gains and losses arising from differences between the actual and the expected return on plan assets are recognized in accumulated other comprehensive income.
Recently Issued Accounting Pronouncements not yet Adopted	In December 2023, the FASB issued ASU 2023-09, Income taxes - Improvements to Income Taxes Disclosures, which amends guidance on to enhance the transparency and decision usefulness of income tax disclosures. It is effective for fiscal years beginning after December 15, 2024. The Company is currently evaluating the impact. In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosure (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires a public entity to disclose additional information about specific expense categories in the notes to financial statements on an annual and interim basis. It is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. The Company is currently evaluating the impact.
Prior Period Reclassification	The amortization expense in the consolidated statements of cash flows in prior periods has been reclassified to conform with the current period presentation. The amortization expense of $305 thousand was reclassified from "other non-cash items" to "depreciation and amortization". The change did not have any impact on the net cash flow used in operating activities.

Basis of Presentation and Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2025

The accompanying unaudited condensed consolidated financial statements include those of the Company and its subsidiaries, MoonLake Immunotherapeutics AG, a Swiss stock corporation (Aktiengesellschaft) registered with the commercial register of the Canton of Zug, Switzerland under the number CHE-433.093.536 ("MoonLake AG"), MoonLake Immunotherapeutics Ltd., a private limited company incorporated in the United Kingdom, and MNLK Immunotherapeutics, Unipessoal Lda, a private limited company incorporated in Portugal, after elimination of all intercompany accounts and transactions. The accompanying unaudited condensed consolidated financial statements and notes hereto have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) as set forth by the Financial Accounting Standards Board (“FASB”) and in conformity with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X for interim financial reporting. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the FASB.

In the opinion of management, all material adjustments necessary for a fair presentation of the financial information, which are of a normal and recurring nature, have been made for the interim periods reported. Results of operations for the three months ended March 31, 2025 are not necessarily indicative of the results for the entire fiscal year or any other period. The unaudited condensed consolidated financial information for the three months ended March 31, 2025 and 2024 have been prepared on the same basis as and should be read in conjunction with MoonLake’s audited financial statements and notes thereto for the year ended December 31, 2024 included in the Annual Report.

In the current year, the Company has changed its presentation from ones to thousands and, as a result, rounding adjustments have been made to amounts disclosed in prior years.

The presentation currency of MoonLake is the U.S. Dollar (“$”) and all amounts are presented as such, unless otherwise indicated. The term “Swiss franc” and “CHF” refer to the legal currency of Switzerland, "GBP" refers to the legal currency of the United Kingdom, and “€” and "Euro" refer to the legal currency of Portugal.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires the Company to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of expenses. The significant judgments, estimates and assumptions relevant to the Company relate to:

•determining whether a transaction should be accounted for as a business combination or an asset acquisition;

•determining whether the in-process research and development expenditure (“IPR&D”) has an alternative future use;

•determining assumptions used in estimating the fair value of share-based compensation;

•estimating the recoverability of the deferred tax asset; and

•estimating the amount of accruals in connection with the completion of clinical trial milestones.

The Company bases its judgments and estimates on various factors and information, which may include, but are not limited to, the Company’s forecasts and future plans, current economic conditions and observable market-based transactions of its own shares, the results of which form the basis for making judgments about the carrying value of assets and liabilities and recorded amounts of expenses that are not readily apparent from other sources. To the extent there are material differences between the Company’s estimates and the actual results, the Company’s future results of operation may be affected.

Segment Information

The Company operates as a single operating segment. The Company’s chief operating decision maker (“CODM”), its Chief Executive Officer, manages the Company’s operations on a stand-alone basis for the purposes of allocating resources and assessing financial performance.

Cash and Cash Equivalents

The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents are recorded at cost, which approximates fair value.

Marketable Securities and Short-Term Investments

The Company invests in short-term marketable securities in the form of debt securities. At the time of purchase, the Company assesses whether such debt security should be classified as held-to-maturity or available-for-sale debt securities.

Debt securities are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Held-to-maturity debt securities are carried at amortized cost, adjusted for accretion of discounts or amortization of premiums to maturity computed under the effective interest method. Such accretion or amortization is included in “other income, net”. Marketable debt securities not classified as held-to-maturity are classified as available-for-sale and reported at fair value.

Net unrealized gains and losses on available-for-sale debt securities are excluded from the determination of earnings and are instead recognized in the “Accumulated other comprehensive income” component of shareholders’ equity until realized. Realized gains and losses on available-for-sale debt securities are computed based upon the historical cost of these securities, using the specific identification method.

Interest income is recognized when earned. Realized gains and losses are included in "other income, net" and the cost of securities sold is determined using the specific-identification method.

Marketable debt securities are classified as either “Cash and cash equivalents” or “Short‑term marketable debt securities” according to their original maturity at the time of acquisition. Changes in unrealized gains and losses pertaining to cash equivalent securities are added back into the consolidated statements of cash flows as those are excluded from the determination of earnings but impact the cash and cash equivalents position.

The Company estimates credit losses expected over the life of financial assets based on historical experience, current conditions and reasonable and supportable forecasts. There is no material impact to the consolidated financial statements given the investments are highly liquid thereby carrying negligible credit loss risk and are all held with reputable companies with a low risk of default.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist of cash accounts in large financial institutions which, at times, may exceed the CHF 100 thousand deposit protection limit in Switzerland, the $250 thousand Federal Deposit Insurance Corporation deposit insurance coverage limit in the United States, the GBP 85 thousand Financial Services Compensation Scheme deposit protection limit in the United Kingdom, or the €100 thousand Fundo de Garantia de Depósitos deposit protection limit in Portugal. The Company believes it is not exposed to significant credit risk due to the financial strength of the depository institutions in which the cash and cash equivalents are held. Additionally, the Company ensures further protection against credit risk by diversifying its cash holdings across a variety of credit institutions, thereby minimizing the potential impact of any adverse events on a single institution. Further, the Company's investment strategy for cash (in excess of current business requirements) is set to invest in short-term marketable debt securities. Management actively monitors credit risk in the investment portfolio. Credit risk exposures are controlled in accordance with policies approved by the board of directors to identify, measure, monitor and control credit risks.

Fair Value Measurements

The Company follows the guidance included in ASC 820, Fair Value Measurement. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.

There are three levels of inputs to fair value measurements:

•Level 1, meaning the use of quoted prices for identical instruments in active markets;

•Level 2, meaning the use of quoted prices for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or are directly or indirectly observable; and

•Level 3, meaning the use of unobservable inputs. Observable market data is used when available.

Transfers between Levels 1, 2 or 3 within the fair value hierarchy are recognized at the end of the reporting period when the respective transaction occurred.

Long-Term Debt

Long-term debt is recognized as the amount of cash proceeds received, net of debt issuance cost incurred. It is subsequently reported at amortized cost. Interest expense is calculated using the effective interest method and any difference between the proceeds (net of debt issuance cost) and the principal amount is recognized through interest expense over the estimated life of the related debt.

Leases

The Company determines if an arrangement is or contains a lease at contract inception. For these arrangements, it is evaluated if the arrangement involves an identified asset that is physically distinct or whether the Company has the right to substantially all of the capacity of an identified asset that is not physically distinct. In arrangements that involve an identified asset, there is also judgment in evaluating if the Company has the right to direct the use of that asset.

MoonLake does not have any finance leases. As of March 31, 2025, the Company has five operating leases related to the office spaces located in (i) Dorfstrasse 29, 6300, Zug, Switzerland (comprised of two leases), (ii) 95 Regent Street, CB2 1AW, Cambridge, England, United Kingdom, and (iii) Rua Manuel Pinto de Azedevo 860, 4150-335, Porto, Portugal (comprised of two leases). The operating leases are recognized on a straight-line basis over the lease term commencing on the date the Company has the right to use the leased property. Right-of-use assets and lease liabilities are measured at the lease commencement date based on the present value of the remaining lease payments over the lease term, determined using the discount rate for the lease at the commencement date. Because the rate implicit in the leases is not readily determinable, the Company uses the incremental borrowing rate as the discount rate, which approximates the interest rate at which the Company could borrow on a collateralized basis with similar terms and payments and in similar economic environments.

Leases with an initial term of 12 months or less that do not have the option to purchase the underlying asset are not recorded on the balance sheet, with lease expense for these leases recognized on a straight-line basis over the lease term commencing on the date the Company has the right to use the leased property.

Property and Equipment

Property and equipment, net is stated at cost, net of accumulated depreciation. Depreciation is computed using the straight-line method based on the estimated useful lives of three to five years. As of March 31, 2025, property and equipment, net relates to information technology, office equipment, and leasehold improvements.

Impairment of Long-Lived Assets

The Company reviews all long-lived assets, which consist of operating lease right-of-use assets, and property and equipment, whenever events or changes in circumstance indicate that these assets may not be recoverable. When evaluating long-lived assets, if the Company concludes that the estimated undiscounted cash flows attributable to the assets are less than their carrying value, the Company recognizes an impairment loss based on the excess of the carrying amount of the assets over their respective fair values.

Research and Development Contract Costs and Accruals

Research and development expenses include employee payroll, consulting, contract research and contract manufacturing costs attributable to research and development activities and are expensed as incurred.

Upfront payments and milestone payments made for the licensing of technology are expensed as research and development expenses in the period in which it is probable that a liability has been incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed.

The Company has entered into various research and development contracts with companies both inside and outside of the United States. These agreements are generally cancellable, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.

Share-Based Compensation

The Company recognizes compensation expense based on estimated fair values for all stock-based payment awards made to eligible employees, members of the board of directors and independent contractors that are expected to vest.

The valuation of stock option awards is determined at the date of grant using the Black-Scholes option pricing model. The Black-Scholes option pricing model requires the Company to make assumptions and judgements about the inputs used in the calculations, such as the fair value of the common stock, expected term, expected volatility of the Company’s common stock, risk-free interest rate and expected dividend yield. The valuation of restricted stock awards is measured by the fair value of the Company’s common stock on the date of the grant.

For all stock options granted, the Company calculated the expected term as the period that share-based awards are expected to be outstanding. The estimate of expected volatility is based on comparative companies’ volatility within the Company's industry. The risk-free rate is based on the yield available on United States Treasury zero-coupon issues corresponding to the expected term of the award.

The fair value of the common stock granted under the ESPP (as defined in Note 14 — Share-Based Compensation) was historically estimated by management with reference to the market-based transaction with its Series A investors, as there was no public market for the common stock.

Share-based payment arrangements are accounted for under the fair value method. Total compensation is measured at grant date, based on the fair value of the award at that date, and recorded in earnings over the period the employees are required to render service. The Company recognizes compensation cost only for those awards expected to meet the service conditions on a straight-line basis over the requisite service period of the award.

Foreign Currency

The functional currency of the Company and its subsidiaries is the U.S. dollar. Balances and transactions denominated in foreign currencies are converted as follows: monetary assets and liabilities are translated using exchange rates in effect at the balance sheet dates and non-monetary assets and liabilities are translated at historical exchange rates. Income and expenses are translated at the daily exchange rate on the respective transaction date.

Gains or losses from foreign currency translation are included in the consolidated statements of operations and comprehensive loss in "other income, net".

Income Taxes

The Company accounts for income taxes by using the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is recorded to the extent it is more likely than not that all or a portion of the Company's deferred tax assets will not be realized. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date.

Net Loss per Class A Ordinary Shares

Basic net loss per Class A Ordinary Share is calculated using the two-class method under which earnings are allocated to both Class A Ordinary Shares and participating securities. Basic net loss per share is calculated by dividing the net loss attributable to Class A Ordinary Shares by the weighted-average number of Class A Ordinary Shares outstanding for the period. The diluted net loss per Class A Ordinary Share is computed by dividing the net loss using the weighted-average number of Class A Ordinary Shares and, if dilutive, potential Class A Ordinary Shares outstanding during the period.

In periods in which the Company reports a net loss attributable to shareholders of Class A Ordinary Shares, diluted net loss per share attributable to shareholders of Class A Ordinary Shares is the same as basic net loss per share attributable to shareholders of Class A Ordinary Shares, since dilutive Class A Ordinary Shares are not assumed to be outstanding if their effect is anti-dilutive.

Acquisitions

The Company evaluates acquisitions of assets and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first assessing whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. On April 29, 2021, MoonLake AG entered into an in-licensing agreement (the “In-License Agreement”) with Merck Healthcare KGaA, Darmstadt, Germany (“MHKDG”) to acquire the Sonelokimab program (the “SLK Program”) and determined that substantially all of the fair value of the gross assets acquired related to IPR&D of SLK. Therefore, this transaction was accounted for as an asset acquisition.

IPR&D represents incomplete technologies that the Company acquires, which at the time of acquisition, are still under development and have no alternative future use. The fair value of such technologies is expensed upon acquisition. A technology is considered to have an alternative future use if it is probable that the Company will use the asset in its current, incomplete state as it existed at the acquisition date, in another research and development project that has not yet commenced, and economic benefit is anticipated from that use. If a technology is determined to have an alternative future use, then the fair value of the program would be recorded as an asset on the balance sheet rather than expensed.

Contingent consideration payments (for example milestone payments due upon the occurrence of a specific event) in asset acquisitions are recognized in the period in which it is probable that a liability has been incurred (unless the contingent consideration meets the definition of a derivative, in which case the amount becomes part of the cost in the asset acquired). Upon recognition of the contingent consideration payment, the amount is expensed if it relates to IPR&D or capitalized if it relates to a developed product which is generally considered to be when clinical trials have been completed and regulatory approval obtained.

Future royalty payments due on net sales will be recognized in cost of goods sold when net sales are recognized.

Pension

The Company accounts for pension assets and liabilities in accordance with ASC 715, Compensation – Retirement Benefits, which requires the recognition of the funded status of pension plans in the Company’s consolidated balance sheet. The liability in respect to defined benefit pension plans is the projected benefit obligation calculated annually by independent actuaries using the projected unit credit method. The projected benefit obligation as of March 31, 2025 represents the actuarial present value of the estimated future payments required to settle the obligation that is attributable to employee services rendered before that date. Service costs for such pension plans, represented in the net periodic pension benefit cost, are included in the personnel expenses of the various functions where the employees are engaged. The other components of net benefit cost are included in the consolidated statements of operations and comprehensive loss separately from the service cost component, in “other income, net.” Plan assets are recorded at their fair value.

Gains or losses arising from plan curtailments or settlements are accounted for at the time they occur. Any net pension asset is limited to the present value of the future economic benefits available to the Company in the form of refunds from the plan or expected reductions in future contributions to the plan. Actuarial gains and losses arising from differences between the actual and the expected return on plan assets are recognized in accumulated other comprehensive income.

Recently Issued Accounting Pronouncements not yet Adopted

In December 2023, the FASB issued ASU 2023-09, Income taxes - Improvements to Income Taxes Disclosures, which amends guidance on to enhance the transparency and decision usefulness of income tax disclosures. It is effective for fiscal years beginning after December 15, 2024. The Company is currently evaluating the impact.

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosure (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires a public entity to disclose additional information about specific expense categories in the notes to financial statements on an annual and interim basis. It is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. The Company is currently evaluating the impact.

Prior Period Reclassification

The amortization expense in the consolidated statements of cash flows in prior periods has been reclassified to conform with the current period presentation. The amortization expense of $305 thousand was reclassified from "other non-cash items" to "depreciation and amortization". The change did not have any impact on the net cash flow used in operating activities.