MoonLake Immunotherapeutics (MLTX) 10-K 29 Feb 24 2023 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 29, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	001-39630
Entity Registrant Name	MOONLAKE IMMUNOTHERAPEUTICS
Entity Incorporation, State or Country Code	E9
Entity Tax Identification Number	98-1711963
Entity Address, Address Line One	Dorfstrasse 29
Entity Address, Postal Zip Code	6300
Entity Address, City or Town	Zug
Entity Address, Country	CH
City Area Code	41
Local Phone Number	415108022
Title of 12(b) Security	Class A ordinary share, par value $0.0001 per share
Trading Symbol	MLTX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 1,120
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement relating to its 2024 Annual Meeting of Shareholders, to be held on or about June 5, 2024, 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.
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Central Index Key	0001821586
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		62,874,637
Common Class C
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,012,120

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Auditor Information [Abstract]
Auditor Firm ID	23
Auditor Name	Baker Tilly US, LLP
Auditor Location	Mountain View, CA

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 451,169,337	$ 39,505,627
Short-term marketable debt securities	59,838,900	32,609,108
Other receivables	1,056,862	217,129
Prepaid expenses - current	2,102,203	4,179,468
Total current assets	514,167,302	76,511,332
Non-current assets
Operating lease right-of-use assets	3,628,480	282,580
Property and equipment, net	320,865	49,389
Prepaid expenses - non-current	8,423,468	0
Total non-current assets	12,372,813	331,969
Total assets	526,540,115	76,843,301
Current liabilities
Trade and other payables	1,837,684	254,972
Short-term portion of operating lease liabilities	1,197,876	153,629
Accrued expenses and other current liabilities	6,930,120	7,256,845
Total current liabilities	9,965,680	7,665,446
Non-current liabilities
Long-term portion operating lease liability	2,499,990	128,951
Pension liability	583,426	282,206
Total non-current liabilities	3,083,416	411,157
Total liabilities	13,049,096	8,076,603
Commitments and contingencies
Equity (deficit)
Additional paid-in capital	609,969,236	129,192,291
Accumulated deficit	(116,657,472)	(80,650,212)
Accumulated other comprehensive income	2,357,621	350,946
Total shareholders’ equity	495,675,683	48,898,296
Noncontrolling interests	17,815,336	19,868,402
Total equity	513,491,019	68,766,698
Total liabilities and equity	526,540,115	76,843,301
Common Class A
Equity (deficit)
Common Shares	6,047	3,898
Common Class C
Equity (deficit)
Common Shares	$ 251	$ 1,373

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022	Apr. 05, 2022	Apr. 28, 2021
Common shares, shares outstanding (in shares)			52,701,111
Common Class A
Common shares, par value (USD per share)	$ 0.0001	$ 0.0001		$ 0.0001
Common shares, shares authorized (in shares)	500,000,000	500,000,000
Common shares, shares issued (in shares)	60,466,453	38,977,600
Common shares, shares outstanding (in shares)	60,466,453	38,977,600
Common Class C
Common shares, par value (USD per share)	$ 0.0001	$ 0.0001
Common shares, shares authorized (in shares)	100,000,000	100,000,000
Common shares, shares issued (in shares)	2,505,476	13,723,511
Common shares, shares outstanding (in shares)	2,505,476	13,723,511

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses
Research and development	$ (31,801,880)	$ (42,048,954)
General and administrative	(22,321,216)	(23,012,463)
Total operating expenses	(54,123,096)	(65,061,417)
Operating loss	(54,123,096)	(65,061,417)
Other income, net	10,138,367	591,732
Loss before income tax	(43,984,729)	(64,469,685)
Income tax expense	(94,388)	(36,366)
Net loss	(44,079,117)	(64,506,051)
Of which: net loss attributable to controlling interests shareholders	(36,007,260)	(49,973,249)
Of which: net loss attributable to noncontrolling interests shareholders	(8,071,857)	(14,532,802)
Net unrealized gain on marketable securities and short-term investments	2,330,101	390,753
Actuarial income (loss) on employee benefit plans	(336,579)	269,893
Other comprehensive income	1,993,522	660,646
Comprehensive loss	(42,085,595)	(63,845,405)
Comprehensive loss attributable to controlling interests shareholders	(34,511,723)	(49,437,461)
Comprehensive loss attributable to noncontrolling interests	$ (7,573,872)	$ (14,407,944)
Weighted-average number of shares, basic (in shares)	49,122,534	29,361,353
Weighted-average number of shares, diluted (in shares)	49,122,534	29,361,353
Basic net loss per share attributable to controlling interest shareholders (USD per share)	$ (0.73)	$ (1.70)
Diluted net loss per share attributable to controlling interest shareholders (USD per share)	$ (0.73)	$ (1.70)
Common Class A
Operating expenses
Weighted-average number of shares, basic (in shares)	49,122,534	29,361,353
Weighted-average number of shares, diluted (in shares)	49,122,534	29,361,353
Basic net loss per share attributable to controlling interest shareholders (USD per share)	$ (0.73)	$ (1.70)
Diluted net loss per share attributable to controlling interest shareholders (USD per share)	$ (0.73)	$ (1.70)

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (DEFICIT) - USD ($)	Total	Conversion Following Business Combination	Conversion Of Class C Into Class A Shares	Common Class A	Common Class C	Previously Reported	Total Shareholders' Equity (Deficit)	Total Shareholders' Equity (Deficit) Conversion Following Business Combination	Total Shareholders' Equity (Deficit) Conversion Of Class C Into Class A Shares	Total Shareholders' Equity (Deficit) Previously Reported	Preferred Stock	Preferred Stock Conversion Following Business Combination	Preferred Stock Previously Reported	Preferred Stock Revision of Prior Period, Adjustment	Common Stock	Common Stock Conversion Following Business Combination	Common Stock Common Class A	Common Stock Common Class A Conversion Following Business Combination	Common Stock Common Class A Conversion Of Class C Into Class A Shares	Common Stock Common Class C	Common Stock Common Class C Conversion Following Business Combination	Common Stock Common Class C Conversion Of Class C Into Class A Shares	Common Stock Previously Reported	Common Stock Revision of Prior Period, Adjustment	Treasury Stock, Common	Treasury Stock, Common Conversion Following Business Combination	Treasury Stock, Common Previously Reported	Treasury Stock, Common Revision of Prior Period, Adjustment	Additional Paid-In Capital	Additional Paid-In Capital Conversion Following Business Combination	Additional Paid-In Capital Conversion Of Class C Into Class A Shares	Additional Paid-In Capital Previously Reported	Accumulated Deficit	Accumulated Deficit Previously Reported	Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Conversion Of Class C Into Class A Shares	Accumulated Other Comprehensive Income Previously Reported	Noncontrolling Interests	Noncontrolling Interests Conversion Of Class C Into Class A Shares
Preferred stock, beginning balance (in shares) at Dec. 31, 2021											22,880,908		680,196	22,200,712
Equity, beginning balance at Dec. 31, 2021	$ (11,645,007)					$ (11,645,007)	$ (11,645,007)			$ (11,645,007)	$ 72,466		$ 72,466		$ 38,537								$ 38,537		$ (6,202)		$ (6,202)		$ 42,061,984			$ 42,061,984	$ (53,643,615)	$ (53,643,615)	$ (168,177)		$ (168,177)
Common stock, beginning balance (in shares) at Dec. 31, 2021															12,161,331								361,528	11,799,803
Held in Treasury, beginning balance (in shares) at Dec. 31, 2021																									(1,942,837)		(57,756)	(1,885,081)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling interests recognized on historical net assets of MoonLake AG in connection with the Business Combination	0						8,346,506				$ (23,939)				$ (12,730)										$ 797				(14,551,870)				22,966,652		(32,404)			$ (8,346,506)
Conversion and transfer of shares between classes (in shares)												(22,880,908)			61,000	(12,161,331)	2,051,961	18,501,284	2,051,961	2,051,961	15,775,472	(2,051,961)				765,483
Conversion of MoonLake Class C Ordinary Shares into Class A Ordinary Shares		$ 1,578	$ 0					$ 1,578	$ 3,536,045			$ (48,527)				$ (25,807)		$ 1,850	$ 205		$ 1,578	$ (205)				$ 1,614				$ 70,870	$ 3,520,306					$ 15,739			$ (3,536,045)
Issuance of Class A ordinary shares upon Business Combination (in shares)																	18,424,355
Issuance of Class A Ordinary Shares upon Business Combination	134,653,204						90,783,936										$ 1,843												90,782,093									43,869,268
Emission fees and capital tax payments on share issuance	(56,240)						(40,078)																						(40,078)									(16,162)
Share-based compensation granted under the equity incentive plan ESPP, ESOP, and reverse vesting of Restricted Founder Shares and 2022 MoonLake Immunotherapeutics Equity Incentive Plan (in shares)																									1,177,354
Share-based compensation granted under the equity incentive plan ESPP, ESOP, reverse vesting of Restricted Founder Shares and 2022 MoonLake Immunotherapeutics Equity Incentive Plan	9,658,568						7,352,777																		$ 3,791				7,348,986									2,305,791
Net loss	(64,506,051)						(49,973,249)																										(49,973,249)					(14,532,802)
Other comprehensive income	660,646						535,788																												535,788			124,858
Equity, end balance at Dec. 31, 2022	$ 68,766,698						48,898,296										$ 3,898			$ 1,373									129,192,291				(80,650,212)		350,946			19,868,402
Common stock, ending balance (in shares) at Dec. 31, 2022				38,977,600	13,723,511												38,977,600			13,723,511
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A ordinary shares upon Business Combination (in shares)				18,501,284	15,775,472
Issuance of Class A Ordinary Shares, net of transaction costs (in shares)				11,700,000
Common stock, ending balance (in shares) at Apr. 05, 2022	52,701,111
Common stock, beginning balance (in shares) at Dec. 31, 2022				38,977,600	13,723,511												38,977,600			13,723,511
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion and transfer of shares between classes (in shares)															333,486		11,218,035			(11,218,035)
Conversion of MoonLake Class C Ordinary Shares into Class A Ordinary Shares	$ 0						52,989,048										$ 1,122			$ (1,122)									52,479,045						510,003			(52,989,048)
Share-based compensation granted under the equity incentive plan ESPP, ESOP, reverse vesting of Restricted Founder Shares and 2022 MoonLake Immunotherapeutics Equity Incentive Plan	7,106,005						5,907,406																						5,907,406									1,198,599
Net loss	(44,079,117)						(36,007,260)																										(36,007,260)					(8,071,857)
Other comprehensive income	1,993,522						1,495,537																												1,495,537			497,985
Issuance of Class A Ordinary Shares, net of transaction costs (in shares)															10,270,818		10,270,818
Issuance of Class A Ordinary Shares, net of transaction costs (Note 12)	482,454,426						482,454,426										$ 1,027												482,453,399
Capital injection from MoonLake to MoonLake AG (Note 12)	(2,750,515)						(60,060,626)																						(60,061,761)						1,135			57,310,111
Refund of stamp duty fees	0						(1,144)																						(1,144)									1,144
Equity, end balance at Dec. 31, 2023	$ 513,491,019						$ 495,675,683										$ 6,047			$ 251									$ 609,969,236				$ (116,657,472)		$ 2,357,621			$ 17,815,336
Common stock, ending balance (in shares) at Dec. 31, 2023				60,466,453	2,505,476												60,466,453			2,505,476

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flow from operating activities
Net loss	$ (44,079,117)	$ (64,506,051)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	13,158	12,358
Share-based compensation expense	7,106,005	9,654,778
Net periodic pension benefit cost for the qualified pension plan	(85,254)	304,031
Other non-cash items	484,762	220,880
Changes in operating assets and liabilities:
Other receivables	(839,733)	(68,355)
Right-of-use assets	(65,513)	0
Prepaid expenses	(6,346,203)	(2,730,373)
Trade and other payables	1,582,712	(1,314,318)
Operating leases liabilities	(222,259)	(152,425)
Accrued expenses and other current liabilities	(326,725)	2,685,576
Net cash flow used in operating activities	(42,778,167)	(55,893,900)
Cash flow from investing activities
Purchase of short-term marketable debt securities	(175,732,711)	(42,226,021)
Proceeds from maturities of short-term marketable debt securities	150,833,021	9,901,437
Purchase of property and equipment	(284,634)	(16,009)
Net cash flow used in investing activities	(25,184,324)	(32,340,593)
Cash flow from financing activities
Issuance of Class A Ordinary Shares, net of transaction costs (Note 12)	482,454,426	0
Stamp duty on capital injection from MoonLake to MoonLake AG (Note 12)	(2,752,918)	0
Proceeds from Business Combination	0	134,646,009
Contribution for par value of Class V Shares	0	42,935
Repayment of loan liability	0	(15,000,000)
Grants of additional shares under ESPP	0	3,791
Net cash flow provided by financing activities	479,701,508	119,692,735
Effect of movements in exchange rates on cash held	(75,307)	8,540
Net change in cash and cash equivalents	411,663,710	31,466,782
Cash and cash equivalents, beginning of period	39,505,627	8,038,845
Cash and cash equivalents, end of period	451,169,337	39,505,627
Supplementary disclosure of cash flow information:
Cash paid for income taxes	41,713	4,312
Non-cash operating lease assets obtained in exchange for lease obligations	3,637,545	435,005
Cash paid for amounts included in the measurement of lease liabilities	$ 422,519	$ 155,552

Overview of the Company

Overview of the Company	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Overview of the Company	Overview of the Company Corporate Information MoonLake Immunotherapeutics is a clinical stage biotechnology company advancing therapies to address significant unmet needs in inflammatory skin and joint diseases. MoonLake Immunotherapeutics is currently a single asset company focused on the development of Sonelokimab (“SLK”), a novel tri-specific IL-17A and IL-17F inhibiting Nanobody that has the potential, based on response levels seen in clinical trials, to drive disease modification in dermatology and rheumatology patients. Unless the context otherwise requires, “MoonLake”, and the “Company” refer to the combined company following the Business Combination (as defined in Note 2 — Business Combination Agreement with Helix and Recapitalization

Business Combination Agreement

Business Combination Agreement with Helix and Recapitalization	12 Months Ended
	Dec. 31, 2023
Reverse Recapitalization [Abstract]
Business Combination Agreement with Helix and Recapitalization	Business Combination Agreement with Helix and Recapitalization On April 5, 2022 (the “Closing Date”), MoonLake Immunotherapeutics, a Cayman Islands exempted company (formerly known as Helix Acquisition Corp.) (prior to the Closing Date, “Helix” and after the Closing Date, “MoonLake” or the “Company”) consummated the previously announced business combination (the “Closing”) pursuant to that certain Business Combination Agreement dated October 4, 2021 (the “Business Combination Agreement”), by and among Helix, 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”), the existing equityholders of MoonLake AG set forth on the signature pages to the Business Combination Agreement and the equityholders of MoonLake AG that executed joinders to the Business Combination Agreement (collectively, the “ML Parties”), Helix Holdings LLC, a Cayman Islands limited liability company and the sponsor of Helix (the “Sponsor”), and the representative of the ML Parties (such transactions contemplated by the Business Combination Agreement collectively, the “Business Combination”). Net proceeds from the Business Combination totaled $134.7 million, which included funds held in Helix’s trust account and the completion of a concurrent PIPE investment. Pursuant to the Business Combination Agreement, approved by the boards of directors of each of MoonLake AG and Helix, (i) the Company changed its name from Helix Acquisition Corp. to MoonLake Immunotherapeutics, and (ii) MoonLake AG merged with and into MoonLake, with MoonLake AG as the surviving company in the Business Combination and, after giving effect to such Business Combination, MoonLake AG as a subsidiary of MoonLake. The Business Combination Agreement provided for, among other things, the following transactions: i. Two business days prior to the Closing Date, the ML Parties and MoonLake AG effectuated a restructuring of MoonLake AG’s share capital to, among other things, (x) convert the Series A preferred shares of MoonLake AG, par value of CHF 0.10 per share, into an equal number of MoonLake AG Common Shares such that the ML Parties held a single class of capital share of MoonLake AG immediately prior to the Closing and (y) approve a capital increase for the issuance of 4,006,736 Class V Voting Shares of MoonLake AG, par value CHF 0.01 per share, to Helix, each Class V Voting Share due to its lower par value having ten times the voting power of a MoonLake AG Common Share (the “Restructuring”). ii. At the Closing, 2,875,000 Class B ordinary shares of Helix, par value $0.0001 per share (the “Class B Ordinary Shares”), constituting all of the then-outstanding Class B Ordinary Shares, were automatically converted into Class A Ordinary Shares on a one-for-one basis. iii. At the Closing, Helix amended and restated its existing memorandum and articles of association to, among other things, establish a share structure consisting of the Class A Ordinary Shares, which carry economic and voting rights, and Class C Ordinary Shares, which carry voting rights but no economic rights. iv. On the Closing Date, Helix paid all unpaid transaction expenses and contributed $134.7 million to MoonLake AG, including $15.0 million loan repayment pursuant to a convertible loan agreement dated March 20, 2022, by and between MoonLake AG and Cormorant Asset Management LP (“Cormorant”), and assigned by Cormorant to Helix on March 31, 2022. v. On the Closing Date, following the Restructuring, Biotechnology Value Fund, L.P., Biotechnology Value Fund II, L.P., and Biotechnology Value Trading Fund OS, L.P. (collectively, the “BVF Shareholders”) assigned all of their MoonLake AG Common Shares to Helix and Helix issued to the BVF Shareholders 18,501,284 Class A Ordinary Shares. vi. On the Closing Date, following the Restructuring, Helix issued 15,775,472 Class C Ordinary Shares to the ML Parties (other than the BVF Shareholders). Please refer to Note 12 — Shareholders’ Equity (Deficit) for additional details on the exchange mechanism adopted. Additionally, on the Closing Date, Helix issued to the PIPE Investors (as defined below in the section entitled “PIPE Financing”) an aggregate of 11,700,000 Class A Ordinary Shares. As of the open of trading on April 6, 2022, the Class A Ordinary Shares, formerly those of Helix, began trading on The Nasdaq Capital Market (“Nasdaq”) under the trading symbol “MLTX”. PIPE Financing On October 4, 2021, concurrently with the execution of the Business Combination Agreement, and subsequently on March 31, 2022 and April 4, 2022, Helix entered into subscription agreements with certain investors (collectively, the “PIPE Investors”, which includes affiliates of the Sponsor and certain existing equityholders of MoonLake AG) pursuant to which, and on the terms and subject to the conditions of which, the PIPE Investors have collectively subscribed for 11,700,000 Class A Ordinary Shares, 11,600,000 shares of which were issued at a price of $10.00 per share for gross proceeds of $116.0 million and 100,000 shares of which were issued to placement agents of the PIPE in satisfaction of an aggregate of $1.0 million of fees owed by Helix to such placement agents. Summary of Net Proceeds The following table summarizes the elements of the net proceeds from the Business Combination: in thousands Investments held in Trust Account $ 115,051 Less cash to cover redemptions of the Class A Ordinary Shares issued by Helix prior to the Closing Date (80,842) Plus PIPE investment 116,000 Less Helix transaction expense (15,520) of which accrued expenses (5,798) of which deferred IPO underwriting fee (4,025) of which other transaction expenses (5,697) Available Closing Date Cash $ 134,689 Summary of Ordinary Shares Issued The following table summarizes the number of Ordinary Shares outstanding immediately following the consummation of the Business Combination: Helix Acquisition Corp. Ordinary Shares prior to the Business Combination 14,805,000 Of which Class A Ordinary Shares (Helix management - IPO private placement shares) 430,000 Of which Class A Ordinary Shares redeemable 11,500,000 Of which Class B Ordinary Shares (Helix management - sponsor promote) 2,875,000 Less redemptions of the Class A Ordinary Shares issued by Helix prior to the Closing Date (8,080,645) Plus issuance of Helix Class A Ordinary Shares to PIPE Investors 11,700,000 Plus issuance of Helix Class A Ordinary Shares to BVF Shareholders 18,501,284 Total MoonLake Class A Ordinary Shares Outstanding at Closing 36,925,639 Plus issuance of Helix Class C Ordinary Shares to ML Parties (other than the BVF Shareholders) 15,775,472 Total MoonLake Class A and Class C Ordinary Shares Outstanding at Closing 52,701,111 Further information about the Business Combination can be found on Form S-1/A filed with the SEC on July 26, 2022, declared effective on August 2, 2022 and to the exhibits included therein, available at www.sec.gov.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Basis of Presentation The accompanying 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 ("MNLK PT"), a private limited company incorporated in Portugal, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). 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 Financial Accounting Standards Board ("FASB"). Pursuant to ASC 805, for financial accounting and reporting purposes, MoonLake AG was deemed the accounting acquirer and Helix was treated as the accounting acquiree, and the Business Combination was accounted for as a reverse recapitalization. Accordingly, the Business Combination was treated as the equivalent of MoonLake AG issuing shares for the net assets of Helix, accompanied by a recapitalization. The net assets of Helix were stated at historical costs, with no goodwill or other intangible assets recorded, and are consolidated with MoonLake AG’s financial statements on the Closing Date. In accordance with the Business Combination Agreement, the ML Parties received 33.638698 Ordinary Shares in the Company for every MoonLake AG Common Share or Series A Preferred Share (the “Exchange Ratio”). The BVF Shareholders received 18,501,284 Class A Ordinary Shares whereas the rest of the ML Parties (excluding the BVF Shareholders) received 15,775,472 Class C Ordinary Shares which can be converted into Class A Ordinary Shares at the discretion of the shareholder (refer to Note 12 — Shareholders’ Equity (Deficit) for further details on the classes of ordinary shares). The number of shares, and the number of shares within the net income (loss) per share held by the ML Parties in MoonLake AG prior to the Business Combination have been adjusted by the Exchange Ratio to reflect the equivalent number of ordinary shares in the Company (identified as “the equivalent of” throughout these consolidated financial statements). Certain MoonLake AG shareholders (ML Parties other than the BVF Shareholders), did not exchange their shares in MoonLake AG for Class A Ordinary Shares in the Company and therefore continued to hold an economic interest in MoonLake AG and Class C Ordinary Shares in the Company. The Company recognized a noncontrolling interest equal to the ML Parties’ (other than the BVF Shareholders) proportionate interest in the net assets of MoonLake AG. All amounts are presented in U.S. Dollar (“$”), 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 “€” refers to euros. 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 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. 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. As of December 31, 2023, the Company considers $129.4 million of short-term marketable debt securities in the form of eurocommercial papers and certificates of deposit to be cash equivalents. As of December 31, 2022, the Company considered $19.9 million of short-term marketable debt securities in the form of eurocommercial papers and certificates of deposit to be cash equivalents. 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 “Interest and dividend income”. 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 (loss)” component of shareholders’ equity (deficit) 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. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Dividend and interest income are recognized when earned. Realized gains and losses are included in "Other income" 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 statement of cash flows as those are excluded from the determination of earnings but impact the cash and cash equivalents position. 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 100,000 deposit protection limit in Switzerland, the $250,000 Federal Deposit Insurance Corporation deposit insurance coverage limit in the United States, the GBP 85,000 Financial Services Compensation Scheme deposit protection limit in the United Kingdom, or the €100,000 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. Segment Information The Company operates as a single operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a stand-alone basis for the purposes of allocating resources, and assessing financial performance. 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 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 Transaction Goods or services received in a share-based payment transaction are measured using a fair value-based measure. Stock-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. 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. Revenue and expenses are translated at the daily exchange rate on the respective accounting date. Gains or losses from foreign currency translation are included in the consolidated statement of operations in "other income, net". The Company recognized foreign currency transaction gain of $151,493 for the year ended December 31, 2023 and a foreign currency transaction gain of $325,317 for the year ended December 31, 2022. 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 Accounting 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 December 31, 2023 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 statement of operations separately from the service cost component, in “ other income (expenses), net 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 (loss). 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 December 31, 2023, the Company has three operating leases related to the office spaces which are located in (i) Dorfstrasse 29, 6300, Zug, Switzerland, (ii) 95 Regent Street, CB2 1AW, Cambridge, England, United Kingdom, and (iii) Rua Manuel Pinto de Azedevo 860, 4150-335, Porto, Portugal. The operating leases are recognized over 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 (“RoU”) 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 and 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. Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which amends guidance on reporting credit losses for assets held at amortized cost basis and available-for-sale debt securities. The FASB also issued subsequent amendments to the initial guidance, ASU 2019-04, ASU 2019-05, ASU 2019-11, and ASU 2020-03 (collectively, “Topic 326”). The Current Expected Credit Losses model requires a company to estimate credit losses expected over the life of the financial assets based on historical experience, current conditions and reasonable and supportable forecasts. The Company adopted this new guidance as of December 31, 2023 upon the loss of its “emerging growth company” status. The adoption did not have a material impact on the balances reported in the Company’s consolidated financial statements. In November 2023, the FASB issued ASU 2023-07, Segment reporting — Improvements to Reportable Segment Disclosures , which amends guidance on reportable segment disclosure requirements. It is effective for fiscal years beginning after December 15, 2023. The Company is currently evaluating the impact. The early adoption option will not be exercised. In December 2023, the FASB issued ASU 2023-09, Income taxes - Improvements to Income Taxes Disclosure, 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. The early adoption option will not be exercised. Large Accelerated Filer Status As of December 31, 2023, the Company is considered a “large accelerated filer” and no longer qualifies as an emerging growth company or smaller reporting company. The Company is required, pursuant to Section 404(b) of the Sarbanes-Oxley Act of 2002, to include in its Annual Report on Form 10-K for the year ended December 31, 2023 an attestation report as to the effectiveness of the Company's internal control over financial reporting that is issued by its independent registered public accounting firm. In addition, beginning with the Company's Quarterly Report on Form 10-Q for the quarter ending March 31, 2024, it will no longer be permitted to take advantage of the reduced reporting requirements applicable to smaller reporting companies.

Risks and Liquidity

Risks and Liquidity	12 Months Ended
	Dec. 31, 2023
Risks and Uncertainties [Abstract]
Risks and Liquidity	Risks and Liquidity Going Concern, Liquidity and Capital Resources The Company incurred a loss of $44.1 million for the year ended December 31, 2023. As of December 31, 2023, the Company’s current assets exceeded its current liabilities by $504.2 million.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following table presents information about the Company's short-term marketable debt securities measured at fair value on a recurring basis and indicate the level in the fair value hierarchy in which the Company classifies the fair value measurement: December 31, 2023 December 31, 2022 Level 2 Total Level 2 Total Eurocommercial Papers $ 109,608,915 $ 109,608,915 $ 42,552,608 $ 42,552,608 Certificates of deposit 79,626,727 79,626,727 9,937,899 9,937,899 Total $ 189,235,642 $ 189,235,642 $ 52,490,507 $ 52,490,507 Cash, accounts payable and accrued liabilities approximate their fair values as of December 31, 2023 and December 31, 2022, due to their short-term nature. Pension plan assets fair value is determined based on Level 2 inputs.

Investments

Investments	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The fair value and amortized cost of investments in short-term marketable debt securities by major security type as of December 31, 2023 and December 31, 2022 are as follows: December 31, 2023 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Eurocommercial Papers $ 107,624,341 $ 1,984,574 $ — $ 109,608,915 Certificates of Deposit 78,890,447 736,280 — 79,626,727 Total $ 186,514,788 $ 2,720,854 $ — $ 189,235,642 Of which classified within cash and cash equivalents 128,197,581 1,199,161 — 129,396,742 Of which classified within short-term marketable debt securities 58,317,207 1,521,693 — 59,838,900 December 31, 2022 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Eurocommercial Papers $ 42,265,129 $ 287,479 $ — $ 42,552,608 Certificates of Deposit 9,834,625 103,274 — 9,937,899 Total $ 52,099,754 $ 390,753 $ — $ 52,490,507 Of which classified within cash and cash equivalents 19,775,171 106,228 — 19,881,399 Of which classified within short-term marketable debt securities 32,324,583 284,525 — 32,609,108 The following table presents the changes in fair values of the Company’s short-term marketable debt securities, classified as Level 2 financial assets, and recognized in accumulated other comprehensive income: Beginning balance, January 1, 2023 $ 390,753 Other comprehensive income before reclassifications 8,751,307 Amounts reclassified from accumulated other comprehensive income (6,421,206) Ending balance, December 31, 2023 $ 2,720,854 As of December 31, 2023, the Company’s marketable debt securities maturities are all due within one year.

Prepaid Expenses

Prepaid Expenses	12 Months Ended
	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses	Prepaid Expenses Prepaid expenses - current December 31, 2023 December 31, 2022 Insurances $ 1,077,478 $ 1,416,597 Non-clinical research and clinical development services 842,729 2,443,863 Other consulting and advisory services 70,018 105,651 Other prepayments 111,978 213,357 Total $ 2,102,203 $ 4,179,468 Prepaid expenses - non-current December 31, 2023 December 31, 2022 Supply and manufacturing services $ 8,423,468 $ — Total $ 8,423,468 $ — Prepaid expenses - non-current relate to advance payments made to a contract manufacturing organization pursuant to a manufacturing run reservation agreement for the commercial-scale manufacturing of Sonelokimab in 2025.

Trade and Other Payables

Trade and Other Payables	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Trade and Other Payables	Trade and Other Payables December 31, 2023 December 31, 2022 Research and development services $ 911,454 $ 31,687 Supply and manufacturing fees payable 553,459 65,979 Rent / leases 108,249 — Other payables 264,522 157,306 Total $ 1,837,684 $ 254,972 December 31, 2023 December 31, 2022 Bonuses and related employees compensation expenses $ 2,780,219 $ 1,109,734 Supply and manufacturing services 1,603,739 — Research and development services and license fees 1,226,281 5,803,432 Consultant and other fees 853,905 218,021 Tax liabilities 367,976 109,826 Legal fees 98,000 15,832 Total $ 6,930,120 $ 7,256,845

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Trade and Other Payables December 31, 2023 December 31, 2022 Research and development services $ 911,454 $ 31,687 Supply and manufacturing fees payable 553,459 65,979 Rent / leases 108,249 — Other payables 264,522 157,306 Total $ 1,837,684 $ 254,972 December 31, 2023 December 31, 2022 Bonuses and related employees compensation expenses $ 2,780,219 $ 1,109,734 Supply and manufacturing services 1,603,739 — Research and development services and license fees 1,226,281 5,803,432 Consultant and other fees 853,905 218,021 Tax liabilities 367,976 109,826 Legal fees 98,000 15,832 Total $ 6,930,120 $ 7,256,845

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	Leases In August 2021, the Company entered into an open-ended office lease agreement, effective November 1, 2021, to lease approximately 2,300 square feet of space on the last two floors of the building located at Dorfstrasse 29, 6300 Zug, Switzerland (the “Office Lease"). The Company estimated the effective duration of the Office Lease at inception and determined a period of 3 years, with expected expiration in November 2024. In December, 2023, the contract was extended, leading to a new estimated effective duration of the lease period of 3 years, with expected expiration in January 2027. On October 9, 2023, the Company entered into an office lease agreement, effective as of October 9, 2023, to lease approximately 3,900 square feet of office space on the fifth floor of the building located at Rua Manuel Pinto de Azedevo 860, 4150-335, Porto, Portugal. This lease has a 3-year initial term, with two extendable periods of 3 years each. It is expected to be extended once until October 2029. On October 13, 2023, the Company entered into an office lease agreement, effective as of October 16, 2023, to lease approximately 6,000 square feet of office space on the first floor of the building located at 95 Regent Street, CB2 1AW, Cambridge, England, United Kingdom. This lease has a 3-year term agreement and is set to expire in October 2026. The weighted average remaining lease term and weighted average discount rate for the operating leases as of December 31, 2023 and December 31, 2022 were as follows: December 31, 2023 December 31, 2022 Weighted average remaining lease term (in months) 39 22 Weighted average discount rate 4.9 % 0.8 % The future minimum annual lease payments under these operating leases as of December 31, 2023 are as follows: Year ending December 31, Amount 2024 $ 1,343,255 2025 1,343,255 2026 1,029,249 2027 95,794 2028 95,794 Thereafter 65,923 Total lease payments 3,973,270 Less imputed interest (275,404) Total lease liability 3,697,866 Less current portion of lease liability (1,197,876) Long-term portion operating lease liability $ 2,499,990 The Company recorded lease expense related to its operating leases of $399,882 and $155,552 for the years ended December 31, 2023 and December 31, 2022, respectively.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company operates a defined benefit pension plan in Switzerland (“the Plan”) and a defined contribution pension plan in the United Kingdom and Portugal, in accordance with local regulations and practices. As of December 31, 2023 the Plan covers the Company’s employees in Switzerland with benefits in the event of death, disability, retirement, or termination of employment. A summary of the changes in projected benefit obligations (“PBO”) and plan assets is presented below: December 31, 2023 December 31, 2022 Beginning PBO $ 1,321,969 $ 1,322,874 Service cost 122,698 451,075 Interest cost 30,639 5,056 Contributions by plan participants 200,424 138,243 Actuarial (gain) / losses 487,991 (374,317) Benefits paid 229,902 (204,695) Foreign currency exchange rates changes 208,608 (16,267) Plan amendment (107,750) — Ending PBO $ 2,494,481 $ 1,321,969 December 31, 2023 December 31, 2022 Beginning fair value of plan assets $ 1,039,763 $ 1,083,014 Expected return on plan assets 36,523 15,522 Return on plan assets above expected return 48,938 (115,877) Contributions by the employer 200,424 138,243 Contributions by plan participants 200,424 138,243 Benefits paid 229,902 (204,695) Foreign currency exchange rates changes 155,082 (14,687) Ending fair value of plan assets $ 1,911,056 $ 1,039,763 Amounts recorded on the consolidated balance sheets: December 31, 2023 December 31, 2022 Fair value of plan assets $ 1,911,056 $ 1,039,763 Present value of projected benefit obligation (2,494,481) (1,321,969) Funded status $ (583,425) $ (282,206) Amounts recorded in accumulated other comprehensive (income) / loss: December 31, 2023 December 31, 2022 Actuarial (gain) / loss - beginning of year $ (101,716) $ 168,177 Actuarial (gain) / loss of current year 444,329 (268,076) Amortization — (1,817) Prior service (cost) / credit recognized in current year (107,750) — Total $ 234,863 $ (101,716) The assumptions used to calculate the ASC 715 liabilities are summarized in the table below: December 31, 2023 December 31, 2022 Discount rate 1.35% p.a. 2.20% p.a. Expected return on plan assets 3.00% p.a. 3.80% p.a. Inflation 1.80% p.a. 1.80% p.a. Long-term expected rate of salary increase 2.30% p.a. 2.30% p.a. Service cost of $122,698 was recognized in the net periodic benefit cost for the year ended December 31, 2023. The allocation of plan assets is presented below: December 31, 2023 December 31, 2022 Equities 34.00 % 34.11 % Bonds 32.00 % 28.89 % Mortgages 4.00 % 3.86 % Liquidity 1.00 % 2.41 % Real estate 26.00% 27.17% Alternative investments 3.00% 3.40% Infrastructure —% 0.16% The fair value of plan assets is determined based on Level 2 inputs. As all members of the Plan are active, no future expected benefit payments are currently in payment and foreseen to occur within the next ten years.

Shareholders_ Equity (Deficit)

Shareholders’ Equity (Deficit)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Shareholders’ Equity (Deficit)	Shareholders’ Equity (Deficit) Class A Ordinary Shares (1) Class C Ordinary Shares (1) Total Number of Shares Authorized Issued Authorized Issued Authorized Issued and Outstanding Balance - January 1, 2023 500,000,000 38,977,600 100,000,000 13,723,511 600,000,000 52,701,111 Issuance of Class A Ordinary Shares — 10,270,818 — — — 10,270,818 Conversion of Class C Ordinary Shares into Class A Ordinary Shares — 11,218,035 — (11,218,035) — — Balance - December 31, 2023 500,000,000 60,466,453 100,000,000 2,505,476 600,000,000 62,971,929 (1) Fully paid-in registered shares with a par value of $0.0001 As of December 31, 2023, the Company had the following classes of shares: Class A Ordinary Shares On April 6, 2022, the Company's Class A Ordinary Shares began trading on The Nasdaq Capital Market ("Nasdaq") under the symbol “MLTX”. As of December 31, 2023, there were 60,466,453 Class A Ordinary Shares issued and outstanding. The Company is authorized to issue up to 500,000,000 Class A Ordinary Shares, par value $0.0001 per share. Holders of Class A Ordinary Shares are entitled to one vote for each share. Class C Ordinary Shares As of December 31, 2023, there were 2,505,476 Class C Ordinary Shares issued and outstanding. The Company is authorized to issue up to 100,000,000 Class C Ordinary Shares, with a par value $0.0001 per share. Each Class C Ordinary Share entitles the holders thereof to one vote per share, but carries no economic rights. At the closing of the Business Combination (the "Closing"), MoonLake, MoonLake AG and each ML Party entered into a Restated and Amended Shareholders' Agreement (the “A&R Shareholders' Agreement”). With the intent to approximate the rights, obligations and restrictions that an ML Party would enjoy if it were a holder of Class A Ordinary Shares, the A&R Shareholders’ Agreement (i) imposes certain transfer and other restrictions on the ML Parties, (ii) provides for the waiver of certain statutory rights and (iii) establishes certain mechanics whereby MoonLake and each of the ML Parties are able to effect the conversion of MoonLake AG Common Shares and Class C Ordinary Shares into a number of Class A Ordinary Shares equal to the Exchange Ratio. In 2022, pursuant to the A&R Shareholders’ Agreement, a ML Party submitted an exchange notice to the Company, pursuant to which the ML Party effected the conversion of 61,000 MoonLake AG Common Shares and 2,051,961 Class C Ordinary Shares into 2,051,961 Class A Ordinary Shares using the Exchange Ratio. In 2023, pursuant to the A&R Shareholders’ Agreement, certain ML Parties submitted exchange notices to the Company, pursuant to which such ML Parties effected, in the aggregate, the conversion of 333,486 MoonLake AG Common Shares and 11,218,035 Class C Ordinary Shares into 11,218,035 Class A Ordinary Shares using the Exchange Ratio. The foregoing description of the A&R Shareholders’ Agreement is not complete and is qualified in its entirety by reference to, and should be read in connection with, the full text of the A&R Shareholders’ Agreement filed as an exhibit on the Company's Current Report on Form 8-K filed with the SEC on April 11, 2022. Equity Offerings For the year ended December 31, 2023, the Company issued 10,270,818 Class A Ordinary Shares under the following: At-the-Market Offering On May 11, 2023, the Company entered into a Sales Agreement (the “May 2023 Sales Agreement”) with Leerink Partners LLC (formerly known as SVB Securities LLC) (“Leerink Partners”), through which the Company could issue and sell up to $200,000,000 of its Class A Ordinary Shares (the “May 2023 ATM Shares”), through Leerink Partners as its sales agent. The May 2023 ATM Shares to be sold under the May 2023 Sales Agreement, if any, would be issued and sold pursuant to the Company's shelf registration statement on Form S-3 (File No. 333-271546), which was declared effective by the SEC on May 9, 2023, and a prospectus supplement thereto filed with the SEC on May 11, 2023. On June 27, 2023, the Company reduced the maximum aggregate offering amount of its Class A Ordinary Shares that could be issued and sold under the May 2023 Sales Agreement to $0 and no longer intends to sell Class A Ordinary Shares under the May 2023 Sales Agreement unless the Company files a further prospectus supplement indicating an amount of shares proposed to be sold. On August 31, 2023, the Company entered into a Sales Agreement with Leerink Partners (the “August 2023 Sales Agreement” and together with the May 2023 Sales Agreement, the “Sales Agreements”), through which the Company could issue and sell up to $350,000,000 of its Class A Ordinary Shares (the “August 2023 ATM Shares”), through Leerink Partners as its sales agent. The August 2023 ATM Shares to be sold under the August 2023 Sales Agreement, if any, would be issued and sold pursuant to the Company’s shelf registration statement on Form S-3 (File No. 333-274286), which was declared effective by the SEC on September 11, 2023, and a prospectus supplement thereto filed with the SEC on August 31, 2023. In May 2023, the Company sold 544,894 Class A Ordinary Shares for gross proceeds of $15.2 million. In December 2023, the Company sold a further 525,924 Class A Ordinary Shares for gross proceeds of $31.7 million. Public Offering of Class A Ordinary Shares On June 27, 2023, the Company entered into an underwriting agreement with SVB Securities LLC and Guggenheim Securities LLC as the representatives of the underwriters named therein, to issue and sell 8,000,000 Class A Ordinary Shares at a public offering price of $50.00 per share (the “Offering”). In addition, the Company granted the underwriters an option for a period of 30 days to purchase up to an additional 1,200,000 Class A Ordinary Shares at the public offering price less the underwriting discounts and commissions (the “Option”), and such Option was exercised in full by the underwriters. The Offering closed on June 30, 2023, and net proceeds from the Offering, including proceeds from the exercise in full by the underwriters of the Option, were $436.7 million, after deducting the underwriting discounts and commissions and the offering expenses in the amount of $23.3 million. Following the completion of the Offering, the Company opted to direct a substantial portion of the net proceeds to MoonLake AG. This was executed as a two-step process: (1) the Company acquired the remaining 22,756 shares of MoonLake AG common stock held in treasury through a share purchase and assignment agreement formally executed on July 09, 2023 ($38.9 million) and (2) the Company contributed additional funds to MoonLake AG’s capital reserves through a cash contribution agreement formally executed on July 10, 2023 ($275 million). A stamp duty tax of $2.8 million was levied on the aforementioned capital contribution which the Company has classified as cash flows from financing activities in order to correctly mirror the underlying nature of the transaction.

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share As a result of the Business Combination, the Company has retroactively restated the weighted average number of outstanding prior to April 5, 2022 to give effect to the Exchange Ratio. The following table sets forth the loss per share calculations for the year ended December 31, 2023 compared to the year ended December 31, 2022: Year Ended December 31, 2023 Year Ended December 31, 2022 Numerator Net loss attributable to controlling interests shareholders $ (36,007,260) $ (49,973,249) Denominator Total weighted average number of outstanding shares 49,122,534 29,361,353 Net loss per share – basic and diluted $ (0.73) $ (1.70) The weighted average number of shares used to calculate the net loss per share – basic for the year ended December 31, 2023 excludes 2,505,476 Class C Ordinary Shares as they do not carry economic rights. In the event that ML Parties (other than Biotechnology Value Fund, L.P., Biotechnology Value Fund II, L.P., and Biotechnology Value Trading Fund OS, L.P.) elected to convert their 74,482 MoonLake AG Common Shares into 2,505,476 Class A Ordinary Shares, the weighted average number of shares outstanding would have been 57,679,106 for the year ended December 31, 2023, resulting in a net loss per share of $0.76. Upon conversion, 2,505,476 Class C Ordinary Shares would be forfeited and there would no longer be any non-controlling interests. Upon conversion, the Company's number of Class A Ordinary Shares outstanding would be 63,886,757 as of February 29, 2024, the date the consolidated financial statements were issued.

Share-based Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Share-based Compensation	Share-based Compensation As of December 31, 2023 the Company had the following share-based compensation arrangements: a. Restricted Founder Shares (as defined below) – created in April 2021 by MoonLake AG (no longer active and fully vested as of April 2023); b. The Employee Share Participation Plan (“ESPP”) – created in July 2021 by MoonLake AG; c. The Employee Stock Option Plan (“ESOP”) – created in July 2021 by MoonLake AG; d. MoonLake Immunotherapeutics 2022 Equity Incentive Plan – created in April 2022 by MoonLake Immunotherapeutics. The purpose of the arrangements is to attract and retain the best available personnel and to provide participants with additional incentive to increase their efforts on behalf and in the best interest of the Company and its subsidiaries. MoonLake AG's compensation plans are settled with Common Shares, and with a number of Class C Ordinary Shares determined by multiplying the number of Common Shares by the Exchange Ratio. The reference to “Common Shares” in this Note 14 refers to common shares in MoonLake AG. As a result of the Business Combination, the Company has adjusted the share numbers related to the Restricted Founder Shares and Common Shares (under the ESPP and ESOP) prior to the Business Combination by the Exchange Ratio. The owners of Common Shares have the right to exchange their Common Shares for a number of Class A Ordinary Shares derived using the Exchange Ratio. In the event MoonLake AG shareholders elect to exchange their Common Shares, such MoonLake AG shareholder forfeits a number of Class C Ordinary Shares equal to the number of Class A Ordinary Shares issued (refer to Note 12 — Shareholders’ Equity (Deficit) - Class C Ordinary Shares ). For the year ended December 31, 2023, the Company has recognized an increase in equity in the consolidated balance sheet, and share-based compensation expense in the consolidated statement of operations of $7.1 million. The share-based compensation expense was driven by the following share-based compensation plans and programs: Compensation Plan Year Ended December 31, 2023 Year Ended December 31, 2022 MoonLake AG Restricted Founder Shares $ 1,574,300 $ 4,840,608 ESPP 3,352,885 3,910,076 ESOP 973,868 539,713 MoonLake Immunotherapeutics 2022 Equity Incentive Plan 1,204,952 364,381 Total share-based compensation expense $ 7,106,005 $ 9,654,778 Of which: included in research and development expense 1,524,715 954,379 Of which: included in general and administrative expense 5,581,290 8,700,399 As of December 31, 2023, 11,079 Common Shares (the equivalent of 372,683 Class C Ordinary Shares) issuable from the authorized conditional capital shares remain available for future grants under the ESPP and the ESOP by MoonLake AG. MoonLake AG - Restricted Founder Shares On April 28, 2021, the shareholders’ agreement between the co-founders, the Series A investors and MoonLake AG imposed a reverse vesting condition on 90% of the total 110,000 Common Shares (the equivalent of 3,700,257 Class C Ordinary Shares) held by each of the three co-founders. Therefore, 99,000 Common Shares (the equivalent of 3,330,231 Class C Ordinary Shares) held by each of the co-founders were subject to these restrictions and considered unvested (the “Restricted Founder Shares”). The Restricted Founder Shares vested on the 28th of each month at a rate of 4.166% over a period of two years until April 28, 2023. In the event of a termination of the contractual relationship of the relevant co-founder before the end of the vesting period, MoonLake AG in first priority, or any third party designated by it, and the other shareholders in second priority pro rata to their shareholdings, had an option to purchase all or a pro rata portion of the leaver shares that remained unvested on the effective day of the termination at nominal value of CHF 0.10 (equivalent of $0.0001) per share. The assumptions used in the valuation of the Restricted Founder Shares awarded are summarized below: Grant date 4/28/2021 Estimated fair value of Restricted Founder Shares on the grant date (USD) (1) 49 Estimated fair value of Restricted Founder Shares on the resignation date of one of the co-founders (USD) (2) 336.39 Purchase price (CHF) 0.10 (1) MoonLake AG estimated the fair value of the Restricted Founder Shares with reference to the market-based transaction with the other Series A Preferred Shares Investors (refer to Note 9 of MoonLake AG's audited consolidated financial statements for the year ended December 31, 2021, as filed by Helix Acquisition Corp. together with its revised definitive proxy soliciting materials with the SEC on March 4, 2022). (2) MoonLake AG estimated the fair value of the Restricted Founder Shares at co-founder’s resignation date by dividing the Company Enterprise Value ($360,000,000) as defined by the Business Combination Agreement by the Company’s fully diluted shares (1,070,196). Grants awarded Program Restricted Founder Shares Awards unvested as of January 1, 2022 4,440,309 Awards vested for the year ended December 31, 2022 (3,330,231) Awards unvested as of January 1, 2023 1,110,078 Awards vested for the year ended December 31, 2023 (1,110,078) Awards unvested as of December 31, 2023 0 Employee Share Participation Plan (ESPP) 2021-2025 - MoonLake AG The ESPP grants will vest 25% on each anniversary of the grant date. In the event of a termination of contractual relationship between the Company and the entitled employee, the awards can be deemed forfeited by MoonLake AG if certain conditions are met. Awards feature an accelerated vesting condition linked to a “Change of Control”, defined as any transfer of shares that results in the proposed acquirer holding more than 50% of the then issued share capital of MoonLake AG or the Company, as the case may be, where all the outstanding awards (whether currently outstanding or granted in the future) will be deemed fully vested. ESPP 2021 Assumptions for the awards issued during the year ended December 31, 2022 Grant date 01/18/2022 Estimated fair value per share of Common Shares on the grant date ($) (1) 336.39 Purchase price (CHF) 0.10 (1) MoonLake AG estimated the fair value of the Common Shares by dividing the Company Enterprise Value (USD 360,000,000) as defined by the Business Combination Agreement by the Company’s fully diluted shares (1,070,196). Grants awarded Program ESPP Awards outstanding as of January 1, 2022 1,060,561 Additional awards granted for the year ended December 31, 2022 1,177,354 Awards outstanding as of January 1. 2023 2,237,915 Of which vested as of January 1, 2023 307,794 Awards granted for the year ended December 31, 2023 — Awards outstanding as of December 31, 2023 2,237,915 Of which vested as of December 31, 2023 1,607,425 As of December 31, 2023, MoonLake AG had $6.2 million of total unrecognized compensation expense related to the ESPP that will be recognized over the weighted average period of 2.05 years. Employee Stock Option Plan (ESOP) 2021-2025 - MoonLake AG The ESOP grants will vest 25% on each anniversary of the grant date. In the event of a termination of the contractual relationship between the Company and the entitled employee, options can be deemed forfeited by MoonLake AG if certain conditions are met. Awards feature an accelerated vesting condition linked to a “Change of Control”, defined as any transfer of shares that results in the proposed acquirer holding more than 50% of the then issued share capital of MoonLake AG or the Company, as the case may be, where all the outstanding awards (whether currently outstanding or granted in the future) will be deemed fully vested. ESOP 2021 Weighted average assumptions for the awards issued during the year ended December 31, 2022 Grant dates 5/1/2022, 6/22/2022 Estimated fair value of the option on the grant date using Black-Scholes model ($) 4.21 Exercise price (USD) 3.64 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 75% Risk-free interest rate (3) 3% Expected dividend rate —% (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company’s industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Weighted average assumptions for the awards issued during the year ended December 31, 2023 Grant dates 01/01/2023, 04/24/2023, 07/03/2023, 07/17/2023, 08/01/2023, 08/07/2023, 08/21/2023, 08/29/2023, 09/01/2023, 09/11/2023 Estimated fair value of the option on the grant date using Black-Scholes model ($) 25.5 Exercise price (USD) 37.1 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 75% Risk-free interest rate (3) 4% Expected dividend rate —% (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company’s industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Grants awarded Program ESOP Awards issued as of January 1, 2022 224,033 Additional awards granted for the year ended December 31, 2022 242,736 Awards issued as of January 1, 2023 466,769 Awards granted for the year ended December 31, 2023 133,446 Awards forfeited for the year ended December 31, 2023 (15,137) Awards outstanding at December 31, 2023 585,078 Of which exercisable as of December 31, 2023 219,223 As of December 31, 2023, MoonLake AG had $4.2 million of total unrecognized compensation expense related to the ESOP that will be recognized over the weighted average period of 2.45 years. MoonLake Immunotherapeutics 2022 Equity Incentive Plan On April 5, 2022 (the “Effective Date”) the Company created the “MoonLake Immunotherapeutics 2022 Equity Incentive Plan” (the “Equity Incentive Plan”) to promote and closely align the interests of employees, officers, non-employee directors and other service providers of MoonLake Immunotherapeutics and its shareholders by providing share-based compensation and other performance-based compensation. The Equity Incentive Plan provides for the grant of options, stock appreciation rights, restricted stock units, restricted stock and other share-based awards and for incentive bonuses, which may be paid in cash, Common Shares or a combination thereof, as determined by the compensation committee of the board of directors or such other committee as designated by the board of directors to administer the Equity Incentive Plan. The Equity Incentive Plan shall remain available for the grant of awards until the 10th anniversary of the Effective Date. Awards made under the Equity Incentive Plan to a person who is initially elected or appointed to the Board, and who is a non-employee director at the time of such initial election or appointment, vests and becomes exercisable in 3 equal yearly installments occurring over the three year period following the date of grant, subject to the non-employee director continuing in service on the Board through each such vesting date. Each subsequent award vests and becomes exercisable on the earlier of (i) the 12-month anniversary of the date of grant, and (ii) the next annual meeting of the Company’s stockholders following the date of grant, subject to the non-employee director continuing in service on the Board through such vesting date. Awards made to employees, officers and other service providers of the Company under the Equity Incentive Plan vest 25% on each anniversary date. In the event of a termination of the contractual relationship between the Company and the beneficiary, options can be deemed forfeited by the Company if certain conditions are met. Awards feature an accelerated vesting condition linked to a “Change of Control”, defined as any transfer of shares that results in the proposed acquirer holding more than 50% of the then issued share capital of MoonLake AG or the Company, as the case may be, where all the outstanding awards (whether currently outstanding or granted in the future) will be deemed fully vested. Weighted average assumptions for the awards issued during the year ended December 31, 2022 Grant date 4/6/2022 Estimated fair value of the option on the grant date using Black-Scholes model ($) 8.25 Exercise price ($) 12.25 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 75% Risk-free interest rate (3) 3% Expected dividend rate - (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company's industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Weighted average assumptions for the awards issued during the year ended December 31, 2023 Grant dates 06/08/2023, 10/11/2023, 10/25/2023, 11/01/2023, 11/06/2023, 11/15/2023, 11/16/2023, 11/20/2023, 11/27/2023, 12/01/2023, 12/04/2023 Estimated fair value of the option on the grant date using Black-Scholes model ($) 25.58 Exercise price ($) 37.22 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 0.75 Risk-free interest rate (3) 4% Expected dividend rate 0 (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company's industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Grants awarded Program MoonLake Immunotherapeutics 2022 Equity Incentive Plan Awards issued as of January 1, 2022 — Awards granted for the year ended December 31, 2022 180,000 Awards issued as of December 31, 2022 180,000 Awards exercisable as of December 31, 2022 — Awards granted for the year ended December 31, 2023 132,400 Awards issued as of December 31, 2023 312,400 Awards exercisable as of December 30, 2023 60,000

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's effective tax rate (“ETR”) was -0.3% and 0.1% for the year ended December 31, 2023, and for the year ended December 31, 2022, respectively. The Company is not aware of any items that would cause the quarterly or period-to-date ETR to be significantly different from the Company's annual ETR. The difference between the income tax provision that would be derived by applying the statutory rate to the Company's loss before income taxes and the income tax provision recorded was primarily attributable to non-deductible expense which includes the Swiss entity's recognition of taxable income associated with the sale of treasury shares from MoonLake AG to MoonLake Immunotherapeutics.. The Company continues to incur losses for the Cayman Island and Swiss entity and its ability to utilize the deferred tax asset related to the tax losses is not considered more likely than not. The Company's main operating affiliate, MoonLake AG, is subject to taxation in the Canton of Zug, Switzerland. For the years ended December 31, 2023 and 2022, the Company did not incur any significant income tax expense or benefit, as the Company incurred tax losses and provided a full valuation allowance. The components of income or loss before income tax were as follows: Year Ended December 31, 2023 Year Ended December 31, 2022 Switzerland $ (43,469,946) $ (62,115,251) Foreign (514,783) (2,354,434) Total $ (43,984,729) $ (64,469,685) The provision for income taxes differs from the amount computed by applying the statutory income tax rate to loss before income taxes as follows: Year Ended December 31, 2023 Year Ended December 31, 2022 Statutory income tax rate 11.8% 11.9% Effect of income taxed at different rates (0.4) % — % Change in prior year estimates (0.5) % 0.1 % Utilization of unrecognized losses 0.6 % — % Change in valuation allowance 0.5 % (10.0) % Non-deductible expense (12.3) % (1.4) % Other — % (0.5) % Effective income tax rate (0.3)% 0.1% Significant components of the Company’s deferred tax assets (liabilities) were: December 31, 2023 December 31, 2022 Intangible assets $ 4,493,559 $ 4,492,435 Defined benefit plan 69,173 33,451 Lease liabilities 56,527 — Net operating loss carry forward 6,715,534 7,210,383 Total deferred tax assets 11,334,793 11,736,269 Operating lease right-of-use assets (55,862) — Total deferred tax liabilities (55,862) — Total deferred tax assets (net) 11,278,931 11,736,269 Valuation allowance (11,278,931) (11,736,269) Total deferred tax (net) $ — $ — As of December 31, 2023, the Company’s net deferred tax assets before valuation allowance were $11.3 million. In assessing the realizability of its deferred tax assets, the Company considers whether it is more likely than not that some portion or all of its deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies in making this assessment. Based on the weight of all evidence, the Company has determined that it is not more likely than not that the net deferred tax assets will be realized. A valuation allowance of $11.3 million has been recorded against the deferred tax assets. As of December 31, 2023, MoonLake AG had net operating losses of approximately $56.6 million of which $12.6 million will expire in 2028 and $44.0 million will expire in 2029. The Company’s net operating losses will not be subject to any limitation due to change in ownership according to Swiss Income Tax Law. The Company has no unrecognized tax benefits and does not expect that uncertain tax benefits will change significantly in the next twelve months.

Commitment and Contingencies

Commitment and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitment and Contingencies	Commitments and Contingencies Commitments The Company has entered into agreements as of December 31, 2023 primarily in regards to the clinical and non-clinical development services with contract research organizations ("CROs"), as well as supply and logistics services with contract manufacturing organizations ("CMOs"), for the advancement of SLK. As of December 31, 2023, the total committed expense under these agreements amounted to $44.2 million, of which $8.4 million are recognized under Prepaid expenses - non-current and the rest remain unrecognized. The Company's In-License Agreement with MHKDG includes contractual milestone payments related to the achievement of pre-specified research, development, regulatory and commercialization events and indemnification provisions, which are common in such agreements. Pursuant to the agreements, the Company is obligated to make research and development and regulatory milestone payments upon the occurrence of certain events. Subject to the terms of the license, additional milestone payments of up to €299.6 million ($331.3 million using a December 31, 2023 exchange rate) are potentially payable upon satisfying specific milestones related to regulatory filing acceptance, first commercial sales, and aggregate annual net sales. The milestone payments are payable in cash. Milestone payments due prior to obtaining regulatory approval will be recorded as research and development expense upon determination that a milestone payment is probable to occur. Milestone payments due after obtaining regulatory approval will be capitalized when and if incurred. The Company will use commercially reasonable efforts to cause the milestones to occur. However, if the Company reasonably determines that a technical failure or commercial failure has occurred with respect to all or a part of the SLK Program, the Company, at its sole discretion, can terminate all or part of the SLK Program. As of December 31, 2023, the Company made a total of €7.5 million ($8.1 million using the then applicable exchange rate) in additional milestone payments. In addition, on May 12, 2023, MoonLake AG entered into an agreement with Research Cooperation Technologies, Inc. (“RCT”) and MHKDG, effective as of June 1, 2023, pursuant to which the Company was granted a royalty-bearing, nonexclusive, sublicensable right and license under RCT’s patents and know-how related to a manufacturing process using an underlying yeast strain, Pichia pastoris, to develop, manufacture, use, sell, offer for sale, and import and otherwise commercialize SLK on a world-wide basis, subject to certain restrictions. This agreement replaces the Company’s sublicense for similar rights under the In-License Agreement. In the aggregate, the Company is required to pay royalties within the range of low to mid-teen percent of net sales under the aforementioned agreements with MHKDG and RCT. Royalties will be recognized in the consolidated statement of operations when net sales are recognized. Office Lease On December 12, 2023, the Company committed to an open-ended lease agreement with an effective start date of January 15, 2024, for additional office space at its corporate headquarters at Dorfstrasse 29, 6300 Zug, Switzerland. The Company estimated the effective duration of the Office Lease at inception and determined a 3-year term, commencing at the effective start date of January 15, 2024.

Segment Information and Geograp

Segment Information and Geographic Data	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Segment Information and Geographic Data	Segment Information and Geographic Data Long-lived assets, net of consisting of property and equipment, and operating lease right-of-use assets by geographical area as of December 31, 2023 are as follows: Country December 31, 2023 December 31, 2022 Switzerland $ 507,392 $ 331,969 United Kingdom 2,704,555 — Portugal 737,398 — Total $ 3,949,345 $ 331,969

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Partial Share Conversion On January 2, 2024, pursuant to the A&R Shareholders’ Agreement, a ML Party submitted an exchange notice to the Company, pursuant to which such ML Party effected the conversion of 44,394 MoonLake AG Common Shares and 1,493,356 Class C Ordinary Shares into 1,493,356 Class A Ordinary Shares using the Exchange Ratio. Please refer to Note 12 — Shareholders’ Equity (Deficit) — Class C Ordinary Shares for more information regarding the conversion mechanics. At-the-Market offering In January and February 2024, the Company sold an aggregate of 914,828 Class A Ordinary shares through the August 2023 Sales Agreement for gross proceeds of $53.3 million, bringing total gross proceeds under the August 2023 Sales Agreement to $85.0 million.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (36,007,260)	$ (49,973,249)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2023 shares	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Dr. Kristian Reich [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On October 16, 2023, Dr. Kristian Reich, the Chief Scientific Officer of the Company, adopted a trading plan intended to satisfy Rule 10b5-1(c). Dr. Reich’s plan provides for the sale, subject to certain conditions, of up to 200,000 Class A Ordinary Shares held directly and indirectly by Dr. Reich. The plan terminated on February 28, 2024.
Name	Dr. Kristian Reich
Title	Chief Scientific Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	October 16, 2023
Arrangement Duration	135 days
Aggregate Available	200,000	200,000
Dr. Jorge Santos da Silva [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On October 17, 2023, Dr. Jorge Santos da Silva, the Chief Executive Officer and a director of the Company, adopted a trading plan intended to satisfy Rule 10b5-1(c). Dr. Santos da Silva’s plan provides for the sale of up to 200,000 Class A Ordinary Shares, subject to certain conditions. The plan terminated on February 29, 2024.
Name	Dr. Jorge Santos da Silva
Title	Chief Executive Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	October 17, 2023
Arrangement Duration	135 days
Aggregate Available	200,000	200,000

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	The accompanying 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 ("MNLK PT"), a private limited company incorporated in Portugal, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). 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 Financial Accounting Standards Board ("FASB"). Pursuant to ASC 805, for financial accounting and reporting purposes, MoonLake AG was deemed the accounting acquirer and Helix was treated as the accounting acquiree, and the Business Combination was accounted for as a reverse recapitalization. Accordingly, the Business Combination was treated as the equivalent of MoonLake AG issuing shares for the net assets of Helix, accompanied by a recapitalization. The net assets of Helix were stated at historical costs, with no goodwill or other intangible assets recorded, and are consolidated with MoonLake AG’s financial statements on the Closing Date. In accordance with the Business Combination Agreement, the ML Parties received 33.638698 Ordinary Shares in the Company for every MoonLake AG Common Share or Series A Preferred Share (the “Exchange Ratio”). The BVF Shareholders received 18,501,284 Class A Ordinary Shares whereas the rest of the ML Parties (excluding the BVF Shareholders) received 15,775,472 Class C Ordinary Shares which can be converted into Class A Ordinary Shares at the discretion of the shareholder (refer to Note 12 — Shareholders’ Equity (Deficit) for further details on the classes of ordinary shares). The number of shares, and the number of shares within the net income (loss) per share held by the ML Parties in MoonLake AG prior to the Business Combination have been adjusted by the Exchange Ratio to reflect the equivalent number of ordinary shares in the Company (identified as “the equivalent of” throughout these consolidated financial statements). Certain MoonLake AG shareholders (ML Parties other than the BVF Shareholders), did not exchange their shares in MoonLake AG for Class A Ordinary Shares in the Company and therefore continued to hold an economic interest in MoonLake AG and Class C Ordinary Shares in the Company. The Company recognized a noncontrolling interest equal to the ML Parties’ (other than the BVF Shareholders) proportionate interest in the net assets of MoonLake AG. All amounts are presented in U.S. Dollar (“$”), 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 “€” refers to euros.
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 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.
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 “Interest and dividend income”. 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 (loss)” component of shareholders’ equity (deficit) 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. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. Dividend and interest income are recognized when earned. Realized gains and losses are included in "Other income" 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 statement of cash flows as those are excluded from the determination of earnings but impact the cash and cash equivalents position.
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 100,000 deposit protection limit in Switzerland, the $250,000 Federal Deposit Insurance Corporation deposit insurance coverage limit in the United States, the GBP 85,000 Financial Services Compensation Scheme deposit protection limit in the United Kingdom, or the €100,000 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.
Segment Information	The Company operates as a single operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a stand-alone basis for the purposes of allocating resources, and assessing financial performance.
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
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 Transaction	Goods or services received in a share-based payment transaction are measured using a fair value-based measure. Stock-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. 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. Revenue and expenses are translated at the daily exchange rate on the respective accounting date.
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.
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 Accounting	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 December 31, 2023 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 statement of operations separately from the service cost component, in “ other income (expenses), net
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 December 31, 2023, the Company has three operating leases related to the office spaces which are located in (i) Dorfstrasse 29, 6300, Zug, Switzerland, (ii) 95 Regent Street, CB2 1AW, Cambridge, England, United Kingdom, and (iii) Rua Manuel Pinto de Azedevo 860, 4150-335, Porto, Portugal. The operating leases are recognized over 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 (“RoU”) 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 and 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.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which amends guidance on reporting credit losses for assets held at amortized cost basis and available-for-sale debt securities. The FASB also issued subsequent amendments to the initial guidance, ASU 2019-04, ASU 2019-05, ASU 2019-11, and ASU 2020-03 (collectively, “Topic 326”). The Current Expected Credit Losses model requires a company to estimate credit losses expected over the life of the financial assets based on historical experience, current conditions and reasonable and supportable forecasts. The Company adopted this new guidance as of December 31, 2023 upon the loss of its “emerging growth company” status. The adoption did not have a material impact on the balances reported in the Company’s consolidated financial statements. In November 2023, the FASB issued ASU 2023-07, Segment reporting — Improvements to Reportable Segment Disclosures , which amends guidance on reportable segment disclosure requirements. It is effective for fiscal years beginning after December 15, 2023. The Company is currently evaluating the impact. The early adoption option will not be exercised. In December 2023, the FASB issued ASU 2023-09, Income taxes - Improvements to Income Taxes Disclosure,

Business Combination Agreemen_2

Business Combination Agreement with Helix and Recapitalization (Tables)	12 Months Ended
	Dec. 31, 2023
Reverse Recapitalization [Abstract]
Summary of Net Proceeds and Ordinary Shares Issued	The following table summarizes the elements of the net proceeds from the Business Combination: in thousands Investments held in Trust Account $ 115,051 Less cash to cover redemptions of the Class A Ordinary Shares issued by Helix prior to the Closing Date (80,842) Plus PIPE investment 116,000 Less Helix transaction expense (15,520) of which accrued expenses (5,798) of which deferred IPO underwriting fee (4,025) of which other transaction expenses (5,697) Available Closing Date Cash $ 134,689 The following table summarizes the number of Ordinary Shares outstanding immediately following the consummation of the Business Combination: Helix Acquisition Corp. Ordinary Shares prior to the Business Combination 14,805,000 Of which Class A Ordinary Shares (Helix management - IPO private placement shares) 430,000 Of which Class A Ordinary Shares redeemable 11,500,000 Of which Class B Ordinary Shares (Helix management - sponsor promote) 2,875,000 Less redemptions of the Class A Ordinary Shares issued by Helix prior to the Closing Date (8,080,645) Plus issuance of Helix Class A Ordinary Shares to PIPE Investors 11,700,000 Plus issuance of Helix Class A Ordinary Shares to BVF Shareholders 18,501,284 Total MoonLake Class A Ordinary Shares Outstanding at Closing 36,925,639 Plus issuance of Helix Class C Ordinary Shares to ML Parties (other than the BVF Shareholders) 15,775,472 Total MoonLake Class A and Class C Ordinary Shares Outstanding at Closing 52,701,111

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of debt securities by level within the fair value hierarchy	The following table presents information about the Company's short-term marketable debt securities measured at fair value on a recurring basis and indicate the level in the fair value hierarchy in which the Company classifies the fair value measurement: December 31, 2023 December 31, 2022 Level 2 Total Level 2 Total Eurocommercial Papers $ 109,608,915 $ 109,608,915 $ 42,552,608 $ 42,552,608 Certificates of deposit 79,626,727 79,626,727 9,937,899 9,937,899 Total $ 189,235,642 $ 189,235,642 $ 52,490,507 $ 52,490,507

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of investments in short-term marketable debt securities	The fair value and amortized cost of investments in short-term marketable debt securities by major security type as of December 31, 2023 and December 31, 2022 are as follows: December 31, 2023 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Eurocommercial Papers $ 107,624,341 $ 1,984,574 $ — $ 109,608,915 Certificates of Deposit 78,890,447 736,280 — 79,626,727 Total $ 186,514,788 $ 2,720,854 $ — $ 189,235,642 Of which classified within cash and cash equivalents 128,197,581 1,199,161 — 129,396,742 Of which classified within short-term marketable debt securities 58,317,207 1,521,693 — 59,838,900 December 31, 2022 Amortized cost Gross unrealized gains Gross unrealized losses Fair value Eurocommercial Papers $ 42,265,129 $ 287,479 $ — $ 42,552,608 Certificates of Deposit 9,834,625 103,274 — 9,937,899 Total $ 52,099,754 $ 390,753 $ — $ 52,490,507 Of which classified within cash and cash equivalents 19,775,171 106,228 — 19,881,399 Of which classified within short-term marketable debt securities 32,324,583 284,525 — 32,609,108
Schedule of fair value changes of marketable securities	The following table presents the changes in fair values of the Company’s short-term marketable debt securities, classified as Level 2 financial assets, and recognized in accumulated other comprehensive income: Beginning balance, January 1, 2023 $ 390,753 Other comprehensive income before reclassifications 8,751,307 Amounts reclassified from accumulated other comprehensive income (6,421,206) Ending balance, December 31, 2023 $ 2,720,854

Prepaid Expenses (Tables)

Prepaid Expenses (Tables)	12 Months Ended
	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Prepaid expenses	Prepaid expenses - current December 31, 2023 December 31, 2022 Insurances $ 1,077,478 $ 1,416,597 Non-clinical research and clinical development services 842,729 2,443,863 Other consulting and advisory services 70,018 105,651 Other prepayments 111,978 213,357 Total $ 2,102,203 $ 4,179,468 Prepaid expenses - non-current December 31, 2023 December 31, 2022 Supply and manufacturing services $ 8,423,468 $ — Total $ 8,423,468 $ —

Trade and Other Payables (Table

Trade and Other Payables (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of trade and other payables, current	December 31, 2023 December 31, 2022 Research and development services $ 911,454 $ 31,687 Supply and manufacturing fees payable 553,459 65,979 Rent / leases 108,249 — Other payables 264,522 157,306 Total $ 1,837,684 $ 254,972

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Schedule of accrued expenses and other current liabilities	December 31, 2023 December 31, 2022 Bonuses and related employees compensation expenses $ 2,780,219 $ 1,109,734 Supply and manufacturing services 1,603,739 — Research and development services and license fees 1,226,281 5,803,432 Consultant and other fees 853,905 218,021 Tax liabilities 367,976 109,826 Legal fees 98,000 15,832 Total $ 6,930,120 $ 7,256,845

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Lease, Cost	The weighted average remaining lease term and weighted average discount rate for the operating leases as of December 31, 2023 and December 31, 2022 were as follows: December 31, 2023 December 31, 2022 Weighted average remaining lease term (in months) 39 22 Weighted average discount rate 4.9 % 0.8 %
Future minimum lease payments	The future minimum annual lease payments under these operating leases as of December 31, 2023 are as follows: Year ending December 31, Amount 2024 $ 1,343,255 2025 1,343,255 2026 1,029,249 2027 95,794 2028 95,794 Thereafter 65,923 Total lease payments 3,973,270 Less imputed interest (275,404) Total lease liability 3,697,866 Less current portion of lease liability (1,197,876) Long-term portion operating lease liability $ 2,499,990

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Defined Benefit Plan, Plan with Projected Benefit Obligation in Excess of Plan Assets	A summary of the changes in projected benefit obligations (“PBO”) and plan assets is presented below: December 31, 2023 December 31, 2022 Beginning PBO $ 1,321,969 $ 1,322,874 Service cost 122,698 451,075 Interest cost 30,639 5,056 Contributions by plan participants 200,424 138,243 Actuarial (gain) / losses 487,991 (374,317) Benefits paid 229,902 (204,695) Foreign currency exchange rates changes 208,608 (16,267) Plan amendment (107,750) — Ending PBO $ 2,494,481 $ 1,321,969 December 31, 2023 December 31, 2022 Beginning fair value of plan assets $ 1,039,763 $ 1,083,014 Expected return on plan assets 36,523 15,522 Return on plan assets above expected return 48,938 (115,877) Contributions by the employer 200,424 138,243 Contributions by plan participants 200,424 138,243 Benefits paid 229,902 (204,695) Foreign currency exchange rates changes 155,082 (14,687) Ending fair value of plan assets $ 1,911,056 $ 1,039,763
Schedule of Defined Benefit Plans Disclosures	Amounts recorded on the consolidated balance sheets: December 31, 2023 December 31, 2022 Fair value of plan assets $ 1,911,056 $ 1,039,763 Present value of projected benefit obligation (2,494,481) (1,321,969) Funded status $ (583,425) $ (282,206)
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)	Amounts recorded in accumulated other comprehensive (income) / loss: December 31, 2023 December 31, 2022 Actuarial (gain) / loss - beginning of year $ (101,716) $ 168,177 Actuarial (gain) / loss of current year 444,329 (268,076) Amortization — (1,817) Prior service (cost) / credit recognized in current year (107,750) — Total $ 234,863 $ (101,716)
Defined Benefit Plan, Assumptions	The assumptions used to calculate the ASC 715 liabilities are summarized in the table below: December 31, 2023 December 31, 2022 Discount rate 1.35% p.a. 2.20% p.a. Expected return on plan assets 3.00% p.a. 3.80% p.a. Inflation 1.80% p.a. 1.80% p.a. Long-term expected rate of salary increase 2.30% p.a. 2.30% p.a.
Defined Benefit Plan, Plan Assets, Allocation	The allocation of plan assets is presented below: December 31, 2023 December 31, 2022 Equities 34.00 % 34.11 % Bonds 32.00 % 28.89 % Mortgages 4.00 % 3.86 % Liquidity 1.00 % 2.41 % Real estate 26.00% 27.17% Alternative investments 3.00% 3.40% Infrastructure —% 0.16%

Shareholders_ Equity (Deficit)

Shareholders’ Equity (Deficit) (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Schedule of Stock Authorized and Issued	Class A Ordinary Shares (1) Class C Ordinary Shares (1) Total Number of Shares Authorized Issued Authorized Issued Authorized Issued and Outstanding Balance - January 1, 2023 500,000,000 38,977,600 100,000,000 13,723,511 600,000,000 52,701,111 Issuance of Class A Ordinary Shares — 10,270,818 — — — 10,270,818 Conversion of Class C Ordinary Shares into Class A Ordinary Shares — 11,218,035 — (11,218,035) — — Balance - December 31, 2023 500,000,000 60,466,453 100,000,000 2,505,476 600,000,000 62,971,929 (1)

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of earnings per share, basic and diluted	The following table sets forth the loss per share calculations for the year ended December 31, 2023 compared to the year ended December 31, 2022: Year Ended December 31, 2023 Year Ended December 31, 2022 Numerator Net loss attributable to controlling interests shareholders $ (36,007,260) $ (49,973,249) Denominator Total weighted average number of outstanding shares 49,122,534 29,361,353 Net loss per share – basic and diluted $ (0.73) $ (1.70)

Share-based Compensation (Table

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount	The share-based compensation expense was driven by the following share-based compensation plans and programs: Compensation Plan Year Ended December 31, 2023 Year Ended December 31, 2022 MoonLake AG Restricted Founder Shares $ 1,574,300 $ 4,840,608 ESPP 3,352,885 3,910,076 ESOP 973,868 539,713 MoonLake Immunotherapeutics 2022 Equity Incentive Plan 1,204,952 364,381 Total share-based compensation expense $ 7,106,005 $ 9,654,778 Of which: included in research and development expense 1,524,715 954,379 Of which: included in general and administrative expense 5,581,290 8,700,399
Schedule of Share-Based Payment Award, Non-Option Equity Instruments, Valuation Assumptions	The assumptions used in the valuation of the Restricted Founder Shares awarded are summarized below: Grant date 4/28/2021 Estimated fair value of Restricted Founder Shares on the grant date (USD) (1) 49 Estimated fair value of Restricted Founder Shares on the resignation date of one of the co-founders (USD) (2) 336.39 Purchase price (CHF) 0.10 (1) MoonLake AG estimated the fair value of the Restricted Founder Shares with reference to the market-based transaction with the other Series A Preferred Shares Investors (refer to Note 9 of MoonLake AG's audited consolidated financial statements for the year ended December 31, 2021, as filed by Helix Acquisition Corp. together with its revised definitive proxy soliciting materials with the SEC on March 4, 2022). (2) MoonLake AG estimated the fair value of the Restricted Founder Shares at co-founder’s resignation date by dividing the Company Enterprise Value ($360,000,000) as defined by the Business Combination Agreement by the Company’s fully diluted shares (1,070,196).
Nonvested Restricted Stock Shares Activity	Grants awarded Program Restricted Founder Shares Awards unvested as of January 1, 2022 4,440,309 Awards vested for the year ended December 31, 2022 (3,330,231) Awards unvested as of January 1, 2023 1,110,078 Awards vested for the year ended December 31, 2023 (1,110,078) Awards unvested as of December 31, 2023 0
Schedule of Nonvested Share Activity	ESPP 2021 Assumptions for the awards issued during the year ended December 31, 2022 Grant date 01/18/2022 Estimated fair value per share of Common Shares on the grant date ($) (1) 336.39 Purchase price (CHF) 0.10 (1) MoonLake AG estimated the fair value of the Common Shares by dividing the Company Enterprise Value (USD 360,000,000) as defined by the Business Combination Agreement by the Company’s fully diluted shares (1,070,196). Grants awarded Program ESPP Awards outstanding as of January 1, 2022 1,060,561 Additional awards granted for the year ended December 31, 2022 1,177,354 Awards outstanding as of January 1. 2023 2,237,915 Of which vested as of January 1, 2023 307,794 Awards granted for the year ended December 31, 2023 — Awards outstanding as of December 31, 2023 2,237,915 Of which vested as of December 31, 2023 1,607,425
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions	ESPP 2021 Assumptions for the awards issued during the year ended December 31, 2022 Grant date 01/18/2022 Estimated fair value per share of Common Shares on the grant date ($) (1) 336.39 Purchase price (CHF) 0.10 (1) MoonLake AG estimated the fair value of the Common Shares by dividing the Company Enterprise Value (USD 360,000,000) as defined by the Business Combination Agreement by the Company’s fully diluted shares (1,070,196). Grants awarded Program ESPP Awards outstanding as of January 1, 2022 1,060,561 Additional awards granted for the year ended December 31, 2022 1,177,354 Awards outstanding as of January 1. 2023 2,237,915 Of which vested as of January 1, 2023 307,794 Awards granted for the year ended December 31, 2023 — Awards outstanding as of December 31, 2023 2,237,915 Of which vested as of December 31, 2023 1,607,425
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions	ESOP 2021 Weighted average assumptions for the awards issued during the year ended December 31, 2022 Grant dates 5/1/2022, 6/22/2022 Estimated fair value of the option on the grant date using Black-Scholes model ($) 4.21 Exercise price (USD) 3.64 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 75% Risk-free interest rate (3) 3% Expected dividend rate —% (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company’s industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Weighted average assumptions for the awards issued during the year ended December 31, 2023 Grant dates 01/01/2023, 04/24/2023, 07/03/2023, 07/17/2023, 08/01/2023, 08/07/2023, 08/21/2023, 08/29/2023, 09/01/2023, 09/11/2023 Estimated fair value of the option on the grant date using Black-Scholes model ($) 25.5 Exercise price (USD) 37.1 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 75% Risk-free interest rate (3) 4% Expected dividend rate —% (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company’s industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Weighted average assumptions for the awards issued during the year ended December 31, 2022 Grant date 4/6/2022 Estimated fair value of the option on the grant date using Black-Scholes model ($) 8.25 Exercise price ($) 12.25 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 75% Risk-free interest rate (3) 3% Expected dividend rate - (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company's industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term. Weighted average assumptions for the awards issued during the year ended December 31, 2023 Grant dates 06/08/2023, 10/11/2023, 10/25/2023, 11/01/2023, 11/06/2023, 11/15/2023, 11/16/2023, 11/20/2023, 11/27/2023, 12/01/2023, 12/04/2023 Estimated fair value of the option on the grant date using Black-Scholes model ($) 25.58 Exercise price ($) 37.22 Expected term of the award on the grant date (years) (1) 6 Expected volatility of the share price (2) 0.75 Risk-free interest rate (3) 4% Expected dividend rate 0 (1) The expected term represents the period that share-based awards are expected to be outstanding. (2) The expected volatility was derived from the historical stock volatilities of comparable peer public companies within the Company's industry. (3) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the measurement date with maturities approximately equal to the expected term.
Share-Based Payment Arrangement, Option, Activity	Grants awarded Program ESOP Awards issued as of January 1, 2022 224,033 Additional awards granted for the year ended December 31, 2022 242,736 Awards issued as of January 1, 2023 466,769 Awards granted for the year ended December 31, 2023 133,446 Awards forfeited for the year ended December 31, 2023 (15,137) Awards outstanding at December 31, 2023 585,078 Of which exercisable as of December 31, 2023 219,223 Grants awarded Program MoonLake Immunotherapeutics 2022 Equity Incentive Plan Awards issued as of January 1, 2022 — Awards granted for the year ended December 31, 2022 180,000 Awards issued as of December 31, 2022 180,000 Awards exercisable as of December 31, 2022 — Awards granted for the year ended December 31, 2023 132,400 Awards issued as of December 31, 2023 312,400 Awards exercisable as of December 30, 2023 60,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The components of income or loss before income tax were as follows: Year Ended December 31, 2023 Year Ended December 31, 2022 Switzerland $ (43,469,946) $ (62,115,251) Foreign (514,783) (2,354,434) Total $ (43,984,729) $ (64,469,685)
Schedule of Effective Income Tax Rate Reconciliation	The provision for income taxes differs from the amount computed by applying the statutory income tax rate to loss before income taxes as follows: Year Ended December 31, 2023 Year Ended December 31, 2022 Statutory income tax rate 11.8% 11.9% Effect of income taxed at different rates (0.4) % — % Change in prior year estimates (0.5) % 0.1 % Utilization of unrecognized losses 0.6 % — % Change in valuation allowance 0.5 % (10.0) % Non-deductible expense (12.3) % (1.4) % Other — % (0.5) % Effective income tax rate (0.3)% 0.1%
Schedule of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets (liabilities) were: December 31, 2023 December 31, 2022 Intangible assets $ 4,493,559 $ 4,492,435 Defined benefit plan 69,173 33,451 Lease liabilities 56,527 — Net operating loss carry forward 6,715,534 7,210,383 Total deferred tax assets 11,334,793 11,736,269 Operating lease right-of-use assets (55,862) — Total deferred tax liabilities (55,862) — Total deferred tax assets (net) 11,278,931 11,736,269 Valuation allowance (11,278,931) (11,736,269) Total deferred tax (net) $ — $ —

Segment Information and Geogr_2

Segment Information and Geographic Data (Tables)	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Long-Lived Assets by Geographic Areas	Long-lived assets, net of consisting of property and equipment, and operating lease right-of-use assets by geographical area as of December 31, 2023 are as follows: Country December 31, 2023 December 31, 2022 Switzerland $ 507,392 $ 331,969 United Kingdom 2,704,555 — Portugal 737,398 — Total $ 3,949,345 $ 331,969

Business Combination Agreemen_3

Business Combination Agreement with Helix and Recapitalization - Narrative (Details)			1 Months Ended		12 Months Ended
	Apr. 05, 2022 USD ($) $ / shares shares	Oct. 04, 2021 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares	May 31, 2023 USD ($) shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Apr. 01, 2022 SFr / shares shares	Apr. 28, 2021 $ / shares
Schedule Of Reverse Recapitalization [Line Items]
Reverse recapitalization, net | $	$ 134,689,000
Repayments of loan liability | $	$ 15,000,000				$ 0	$ 15,000,000
Sale of stock (in shares)			525,924	544,894
Sale of stock, consideration received on transaction | $			$ 31,700,000	$ 15,200,000
PIPE Investors
Schedule Of Reverse Recapitalization [Line Items]
Sale of stock (in shares)		11,600,000
Issuance price per share (USD per share) | $ / shares		$ 10
Sale of stock, consideration received on transaction | $		$ 116,000,000
IPO Private Placement Shares
Schedule Of Reverse Recapitalization [Line Items]
Sale of stock (in shares)		100,000
Aggregate fees | $		$ 1,000,000
Series A Preferred Shares
Schedule Of Reverse Recapitalization [Line Items]
Preferred stock, par value (CHF per share) | SFr / shares							SFr 0.10
Class V Voting Stock
Schedule Of Reverse Recapitalization [Line Items]
Common shares, shares authorized (in shares)							4,006,736
Common shares, par value (USD per share) | SFr / shares							SFr 0.01
Common stock, votes per share multiplier							10
Class B Ordinary Shares
Schedule Of Reverse Recapitalization [Line Items]
Common shares, par value (USD per share) | $ / shares	$ 0.0001
Conversion of stock, shares converted	2,875,000
Common stock, conversion ratio (in shares)	1
Common Class A
Schedule Of Reverse Recapitalization [Line Items]
Common shares, shares authorized (in shares)			500,000,000		500,000,000	500,000,000
Common shares, par value (USD per share) | $ / shares			$ 0.0001		$ 0.0001	$ 0.0001		$ 0.0001
Issuance of Class A ordinary shares upon Business Combination (in shares)	18,501,284
Preferred Shares purchased by a director following his appointment as chairman of the board of directors (in shares)	11,700,000
Sale of stock (in shares)		11,700,000			10,270,818
Common Class C
Schedule Of Reverse Recapitalization [Line Items]
Common shares, shares authorized (in shares)			100,000,000		100,000,000	100,000,000
Common shares, par value (USD per share) | $ / shares			$ 0.0001		$ 0.0001	$ 0.0001
Issuance of Class A ordinary shares upon Business Combination (in shares)	15,775,472
Issuance of Helix Class C ordinary shares to ML parties (other than the BVF shareholders) (in shares)	15,775,472

Business Combination Agreemen_4

Business Combination Agreement with Helix and Recapitalization - Summary of Net Proceeds (Details) $ in Thousands	Apr. 05, 2022 USD ($)
Reverse Recapitalization [Abstract]
Investments held in Trust Account	$ 115,051
Less cash to cover redemptions of the Class A Ordinary Shares issued by Helix prior to the Closing Date	(80,842)
Plus PIPE investment	116,000
Less Helix transaction expense	(15,520)
of which accrued expenses	(5,798)
of which deferred IPO underwriting fee	(4,025)
of which other transaction expenses	(5,697)
Available Closing Date Cash	$ 134,689

Business Combination Agreemen_5

Business Combination Agreement with Helix and Recapitalization - Ordinary Shares Issued (Details) - shares	Apr. 05, 2022	Apr. 04, 2022	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)	52,701,111
Common Class A
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)			60,466,453	38,977,600
Issuance of Class A Ordinary Shares, net of transaction costs (in shares)	11,700,000
Plus issuance of helix class A ordinary shares to BVF shareholders (in shares)	18,501,284
Total MoonLake class A ordinary Shares outstanding at closing (in shares)	36,925,639
Common Class C
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)			2,505,476	13,723,511
Plus issuance of helix class A ordinary shares to BVF shareholders (in shares)	15,775,472
Issuance of Helix Class C ordinary shares to ML parties (other than the BVF shareholders) (in shares)	15,775,472
Helix Acquisition Corp.
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)		14,805,000
Helix Acquisition Corp. | Common Class A
Schedule Of Reverse Recapitalization [Line Items]
Less redemptions of class A ordinary shares of the class A ordinary shares issued by Helix prior to the closing date (in shares)		(8,080,645)
Helix Acquisition Corp. | Common class A, private placement
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)		430,000
Helix Acquisition Corp. | Common class A, redeemable
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)		11,500,000
Helix Acquisition Corp. | Class B Ordinary Shares
Schedule Of Reverse Recapitalization [Line Items]
Shares outstanding (in shares)		2,875,000

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Details)		12 Months Ended
	Apr. 05, 2022 shares	Dec. 31, 2023 USD ($) lease	Dec. 31, 2022 USD ($)
Class of Stock [Line Items]
Exchange ratio	33.638698
Debt securities, available-for-sale		$ 189,235,642	$ 52,490,507
Foreign currency transaction gain (loss)		$ 151,493	325,317
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income, net
Number of operating leases | lease		3
Of which classified within cash and cash equivalents
Class of Stock [Line Items]
Debt securities, available-for-sale		$ 129,396,742	$ 19,881,399
Minimum
Class of Stock [Line Items]
Property and equipment, useful life		3 years
Maximum
Class of Stock [Line Items]
Property and equipment, useful life		5 years
Common Class A
Class of Stock [Line Items]
Issuance of Class A ordinary shares upon Business Combination (in shares) | shares	18,501,284
Common Class C
Class of Stock [Line Items]
Issuance of Class A ordinary shares upon Business Combination (in shares) | shares	15,775,472

Risks and Liquidity (Details)

Risks and Liquidity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Risks and Uncertainties [Abstract]
Net loss	$ 44,079,117	$ 64,506,051
Excess of current assets less current liabilities	504,200,000
Unrestricted cash	$ 451,200,000

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Short-term marketable debt securities	$ 59,838,900	$ 32,609,108
Total	189,235,642	52,490,507
Eurocommercial Papers
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Short-term marketable debt securities	109,608,915	42,552,608
Certificates of Deposit
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Short-term marketable debt securities	79,626,727	9,937,899
Level 2
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Total	189,235,642	52,490,507
Level 2 | Eurocommercial Papers
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Short-term marketable debt securities	109,608,915	42,552,608
Level 2 | Certificates of Deposit
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Short-term marketable debt securities	$ 79,626,727	$ 9,937,899

Investments - Schedule of Fair

Investments - Schedule of Fair Value and Amortized Cost of Investments (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	$ 186,514,788	$ 52,099,754
Gross unrealized gains	2,720,854	390,753
Gross unrealized losses	0	0
Fair value	189,235,642	52,490,507
Of which classified within cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	128,197,581	19,775,171
Gross unrealized gains	1,199,161	106,228
Gross unrealized losses	0	0
Fair value	129,396,742	19,881,399
Of which classified within short-term marketable debt securities
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	58,317,207	32,324,583
Gross unrealized gains	1,521,693	284,525
Gross unrealized losses	0	0
Fair value	59,838,900	32,609,108
Eurocommercial Papers
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	107,624,341	42,265,129
Gross unrealized gains	1,984,574	287,479
Gross unrealized losses	0	0
Fair value	109,608,915	42,552,608
Certificates of Deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	78,890,447	9,834,625
Gross unrealized gains	736,280	103,274
Gross unrealized losses	0	0
Fair value	$ 79,626,727	$ 9,937,899

Investments - FV changes (Detai

Investments - FV changes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain (Loss) [Roll Forward]
Other comprehensive income before reclassifications	$ (2,330,101)	$ (390,753)
Level 2
Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain (Loss) [Roll Forward]
Gross unrealized gain (loss), beginning balance	390,753
Other comprehensive income before reclassifications	8,751,307
Amounts reclassified from accumulated other comprehensive income	(6,421,206)
Gross unrealized gain (loss), ending balance	$ 2,720,854	$ 390,753

Prepaid Expenses (Details)

Prepaid Expenses (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Prepaid expenses - current
Insurances	$ 1,077,478	$ 1,416,597
Non-clinical research and clinical development services	842,729	2,443,863
Other consulting and advisory services	70,018	105,651
Other prepayments	111,978	213,357
Total	2,102,203	4,179,468
Prepaid expenses - non-current
Supply and manufacturing services	8,423,468	0
Total	$ 8,423,468	$ 0

Trade and Other Payables (Detai

Trade and Other Payables (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Research and development services	$ 911,454	$ 31,687
Supply and manufacturing fees payable	553,459	65,979
Rent / leases	108,249	0
Other payables	264,522	157,306
Total	$ 1,837,684	$ 254,972

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Bonuses and related employees compensation expenses	$ 2,780,219	$ 1,109,734
Supply and manufacturing services	1,603,739	0
Research and development services and license fees	1,226,281	5,803,432
Consultant and other fees	853,905	218,021
Tax liabilities	367,976	109,826
Legal fees	98,000	15,832
Total	$ 6,930,120	$ 7,256,845

Leases - Narrative (Details)

Leases - Narrative (Details)			1 Months Ended	12 Months Ended
	Oct. 13, 2023 ft²	Oct. 09, 2023 ft² period	Aug. 31, 2021 ft²	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 12, 2023
Lessee, Lease, Description [Line Items]
Lessee, operating lease, lease term extension | period		2
Lease expense | $				$ 399,882	$ 155,552
Office Lease
Lessee, Lease, Description [Line Items]
Square foot of leased space			2,300
Lessee, operating lease, term of contract			3 years	3 years		3 years
Porto Office
Lessee, Lease, Description [Line Items]
Square foot of leased space		3,900
Lessee, operating lease, term of contract		3 years
Lessee, operating lease, renewal term		3 years
Cambridge Office
Lessee, Lease, Description [Line Items]
Square foot of leased space	6,000
Lessee, operating lease, term of contract	3 years

Leases - Schedule of Weighted A

Leases - Schedule of Weighted Average Lease Term And Discount Rate (Details)	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Weighted average remaining lease term (in months)	39 months	22 months
Weighted average discount rate	4.90%	0.80%

Leases - Future Lease Payments

Leases - Future Lease Payments (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 1,343,255
2025	1,343,255
2026	1,029,249
2027	95,794
2028	95,794
Thereafter	65,923
Total lease payments	3,973,270
Less imputed interest	(275,404)
Total lease liability	3,697,866
Less current portion of lease liability	(1,197,876)	$ (153,629)
Long-term portion operating lease liability	$ 2,499,990	$ 128,951

Employee Benefit Plans - Narrat

Employee Benefit Plans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Service cost	$ 122,698	$ 451,075

Employee Benefit Plans - Change

Employee Benefit Plans - Changes in Summary of PBO And Plan Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning PBO	$ 1,321,969	$ 1,322,874
Service cost	122,698	451,075
Interest cost	30,639	5,056
Contributions by plan participants	200,424	138,243
Actuarial (gain) / losses	487,991	(374,317)
Benefits paid	229,902	(204,695)
Foreign currency exchange rates changes	208,608	(16,267)
Plan amendment	(107,750)	0
Ending PBO	2,494,481	1,321,969
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning fair value of plan assets	1,039,763	1,083,014
Expected return on plan assets	36,523	15,522
Return on plan assets above expected return	48,938	(115,877)
Contributions by the employer	200,424	138,243
Contributions by plan participants	200,424	138,243
Benefits paid	229,902	(204,695)
Foreign currency exchange rates changes	155,082	(14,687)
Ending fair value of plan assets	$ 1,911,056	$ 1,039,763

Employee Benefit Plans - Amount

Employee Benefit Plans - Amounts Recorded on the Balance Sheet (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Fair value of plan assets	$ 1,911,056	$ 1,039,763
Present value of projected benefit obligation	(2,494,481)	(1,321,969)
Funded status	$ (583,425)	$ (282,206)

Employee Benefit Plans - Chan_2

Employee Benefit Plans - Changes in Pre-Tax AOCI (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan, AOCI Rollforward [Roll Forward]
Actuarial (gain) / loss - beginning of year	$ (101,716)	$ 168,177
Actuarial (gain) / loss of current year	444,329	(268,076)
Amortization	0	(1,817)
Prior service (cost) / credit recognized in current year	(107,750)	0
Total	$ 234,863	$ (101,716)

Employee Benefit Plans - Assump

Employee Benefit Plans - Assumptions used to calculate liabilities (Details)	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Discount rate	1.35%	2.20%
Expected return on plan assets	3%	3.80%
Inflation	1.80%	1.80%
Long-term expected rate of salary increase	2.30%	2.30%

Employee Benefit Plans - Alloca

Employee Benefit Plans - Allocation Percentage (Details)	Dec. 31, 2023	Dec. 31, 2022
Equities
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	34%	34.11%
Bonds
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	32%	28.89%
Mortgages
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	4%	3.86%
Liquidity
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	1%	2.41%
Real estate
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	26%	27.17%
Alternative investments
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	3%	3.40%
Infrastructure
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Defined benefit plan, plan assets, actual allocation, percentage	0%	0.16%

Shareholders_ Equity (Deficit_2

Shareholders’ Equity (Deficit) - Schedule of Stock Authorized and Issued (Details) - $ / shares		12 Months Ended
	Apr. 05, 2022	Dec. 31, 2023	Dec. 31, 2022	Apr. 28, 2021
Total Number of Shares
Authorized, beginning balance (in shares)		600,000,000
Shares issued, beginning balance (in shares)		52,701,111
Authorized, ending balance (in shares)		600,000,000	600,000,000
Shares issued, ending balance (in shares)		62,971,929	52,701,111
Common Class A
Common Shares
Authorized, beginning balance (in shares)		500,000,000
Issued, beginning balance (in shares)		38,977,600
Issuance of shares under the ATM facility (in shares)	11,700,000
Authorized, ending balance (in shares)		500,000,000	500,000,000
Issued, ending balance (in shares)		60,466,453	38,977,600
Total Number of Shares
Issuance of shares under the ATM facility (in shares)	11,700,000
Common stock, par value (CHF/USD per share)		$ 0.0001	$ 0.0001	$ 0.0001
Common Class C
Common Shares
Authorized, beginning balance (in shares)		100,000,000
Issued, beginning balance (in shares)		13,723,511
Authorized, ending balance (in shares)		100,000,000	100,000,000
Issued, ending balance (in shares)		2,505,476	13,723,511
Total Number of Shares
Common stock, par value (CHF/USD per share)		$ 0.0001	$ 0.0001
Common Shares
Common Shares
Issuance of shares under the ATM facility (in shares)		10,270,818
Conversion of Class C Ordinary Shares into Class A Ordinary Shares (in shares)		333,486	61,000
Total Number of Shares
Issuance of shares under the ATM facility (in shares)		10,270,818
Common Shares | Common Class A
Common Shares
Authorized, beginning balance (in shares)		500,000,000
Issued, beginning balance (in shares)		38,977,600
Issuance of shares under the ATM facility (in shares)		10,270,818
Conversion of Class C Ordinary Shares into Class A Ordinary Shares (in shares)		11,218,035	2,051,961
Authorized, ending balance (in shares)		500,000,000	500,000,000
Issued, ending balance (in shares)		60,466,453	38,977,600
Total Number of Shares
Issuance of shares under the ATM facility (in shares)		10,270,818
Common stock, par value (CHF/USD per share)		$ 0.0001
Common Shares | Common Class A | Conversion Of Class C into Class A
Common Shares
Conversion of Class C Ordinary Shares into Class A Ordinary Shares (in shares)		11,218,035
Common Shares | Common Class C
Common Shares
Authorized, beginning balance (in shares)		100,000,000
Issued, beginning balance (in shares)		13,723,511
Conversion of Class C Ordinary Shares into Class A Ordinary Shares (in shares)		(11,218,035)	2,051,961
Authorized, ending balance (in shares)		100,000,000	100,000,000
Issued, ending balance (in shares)		2,505,476	13,723,511
Total Number of Shares
Common stock, par value (CHF/USD per share)		$ 0.0001
Common Shares | Common Class C | Conversion Of Class C into Class A
Common Shares
Conversion of Class C Ordinary Shares into Class A Ordinary Shares (in shares)		(11,218,035)

Shareholders_ Equity (Deficit_3

Shareholders’ Equity (Deficit) - Narrative (Details)					1 Months Ended		12 Months Ended
	Jul. 10, 2023 USD ($) shares	Jun. 30, 2023 USD ($)	Jun. 27, 2023 USD ($) $ / shares shares	Oct. 04, 2021 shares	Dec. 31, 2023 USD ($) vote $ / shares shares	May 31, 2023 USD ($) shares	Dec. 31, 2023 vote $ / shares shares	Dec. 31, 2022 $ / shares shares	Aug. 31, 2023 USD ($)	May 11, 2023 USD ($)	Apr. 05, 2022 shares	Dec. 31, 2021 shares	Apr. 28, 2021 $ / shares shares
Class of Stock [Line Items]
Common shares, shares outstanding (in shares)											52,701,111
Sale of stock (in shares)					525,924	544,894
Sale of stock, consideration received on transaction | $					$ 31,700,000	$ 15,200,000
Stamp duty tax | $	$ (2,800,000)
MoonLake AG
Class of Stock [Line Items]
Common shares, shares outstanding (in shares)													110,000
MoonLake Immunotherapeutics | MoonLake AG
Class of Stock [Line Items]
Sale of stock, consideration received on transaction | $	38,900,000
Proceeds from contributions from parent | $	$ 275,000,000
Underwriting Agreement
Class of Stock [Line Items]
Sale of stock (in shares)			8,000,000
Sale of stock, consideration received on transaction | $		$ 436,700,000
Payments of stock issuance costs | $		$ 23,300,000
Issuance price per share (USD per share) | $ / shares			$ 50
Underwriting Agreement | MoonLake Immunotherapeutics | MoonLake AG
Class of Stock [Line Items]
Sale of stock (in shares)	22,756
Over-Allotment Option
Class of Stock [Line Items]
Sale of stock (in shares)			1,200,000
Sale of stock, option to purchase, term			30 days
ATM Shares | May 2023 Sales Agreement
Class of Stock [Line Items]
Sale of stock, authorized amount | $										$ 200,000,000
Sale of stock, remaining authorized repurchase amount | $			$ 0
ATM Shares | August 2023 Sales Agreement
Class of Stock [Line Items]
Sale of stock, authorized amount | $									$ 350,000,000
Common Stock
Class of Stock [Line Items]
Common shares, shares outstanding (in shares)												12,161,331
Conversion and transfer of shares between classes (in shares)							333,486	61,000
Common Class A
Class of Stock [Line Items]
Common shares, shares issued (in shares)					60,466,453		60,466,453	38,977,600
Common shares, shares outstanding (in shares)					60,466,453		60,466,453	38,977,600
Common shares, shares authorized (in shares)					500,000,000		500,000,000	500,000,000
Common shares, par value (USD per share) | $ / shares					$ 0.0001		$ 0.0001	$ 0.0001					$ 0.0001
Sale of stock (in shares)				11,700,000			10,270,818
Common Class A | Common Stock
Class of Stock [Line Items]
Common shares, shares issued (in shares)					60,466,453		60,466,453	38,977,600
Common shares, shares outstanding (in shares)					60,466,453		60,466,453	38,977,600
Common shares, shares authorized (in shares)					500,000,000		500,000,000	500,000,000
Common shares, par value (USD per share) | $ / shares					$ 0.0001		$ 0.0001
Common shares, votes per share | vote					1		1
Conversion and transfer of shares between classes (in shares)							11,218,035	2,051,961
Common Class C
Class of Stock [Line Items]
Common shares, shares issued (in shares)					2,505,476		2,505,476	13,723,511
Common shares, shares outstanding (in shares)					2,505,476		2,505,476	13,723,511
Common shares, shares authorized (in shares)					100,000,000		100,000,000	100,000,000
Common shares, par value (USD per share) | $ / shares					$ 0.0001		$ 0.0001	$ 0.0001
Common Class C | MoonLake AG
Class of Stock [Line Items]
Common shares, shares outstanding (in shares)													3,700,257
Common Class C | Common Stock
Class of Stock [Line Items]
Common shares, shares issued (in shares)					2,505,476		2,505,476	13,723,511
Common shares, shares outstanding (in shares)					2,505,476		2,505,476	13,723,511
Common shares, shares authorized (in shares)					100,000,000		100,000,000	100,000,000
Common shares, par value (USD per share) | $ / shares					$ 0.0001		$ 0.0001
Common shares, votes per share | vote					1		1
Conversion and transfer of shares between classes (in shares)							(11,218,035)	2,051,961

Net Loss per Share - Calculatio

Net Loss per Share - Calculation of Net Loss per Share (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator
Net loss attributable to controlling interests shareholders	$ (36,007,260)	$ (49,973,249)
Denominator
Total weighted average number of outstanding shares, basic (in shares)	49,122,534	29,361,353
Total weighted average number of outstanding shares, diluted (in shares)	49,122,534	29,361,353
Net loss per share - basic (in USD per share)	$ (0.73)	$ (1.70)
Net loss per share - diluted (in USD per share)	$ (0.73)	$ (1.70)

Net Loss per Share - Narrative

Net Loss per Share - Narrative (Details) - $ / shares		12 Months Ended
	Apr. 05, 2022	Dec. 31, 2023	Dec. 31, 2022	Feb. 29, 2024	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of shares, basic (in shares)		49,122,534	29,361,353
Weighted-average number of shares, diluted (in shares)		49,122,534	29,361,353
Net loss per share - basic (in USD per share)		$ 0.73	$ 1.70
Net loss per share - diluted (in USD per share)		$ 0.73	$ 1.70
Number of shares outstanding (in shares)	52,701,111
Pro forma
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average number of shares, basic (in shares)		57,679,106
Weighted-average number of shares, diluted (in shares)		57,679,106
Net loss per share - basic (in USD per share)		$ 0.76
Net loss per share - diluted (in USD per share)		$ 0.76
Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares outstanding (in shares)					12,161,331
ML parties other than BVF shareholders
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
MoonLake AG common shares (in shares)		74,482
Common Class C
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares, shares issued (in shares)		2,505,476	13,723,511
Stock converted (in shares)	15,775,472
Number of shares outstanding (in shares)		2,505,476	13,723,511
Common Class C | Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares, shares issued (in shares)		2,505,476	13,723,511
Number of shares outstanding (in shares)		2,505,476	13,723,511
Common Class C | ML parties other than BVF shareholders | Pro forma
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock forfeited (in shares)		2,505,476
Common Class A
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares, shares issued (in shares)		60,466,453	38,977,600
Weighted-average number of shares, basic (in shares)		49,122,534	29,361,353
Weighted-average number of shares, diluted (in shares)		49,122,534	29,361,353
Net loss per share - basic (in USD per share)		$ 0.73	$ 1.70
Net loss per share - diluted (in USD per share)		$ 0.73	$ 1.70
Number of shares outstanding (in shares)		60,466,453	38,977,600
Common Class A | Pro forma | Subsequent Event
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares outstanding (in shares)				63,886,757
Common Class A | Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares, shares issued (in shares)		60,466,453	38,977,600
Number of shares outstanding (in shares)		60,466,453	38,977,600
Common Class A | ML parties other than BVF shareholders | Pro forma
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock converted (in shares)		2,505,476

Share-based Compensation - Narr

Share-based Compensation - Narrative (Details)			12 Months Ended
	Apr. 05, 2022 installment shares	Apr. 28, 2021 $ / shares shares	Dec. 31, 2023 USD ($) co-founder $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 shares	Apr. 28, 2021 SFr / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense | $			$ 7,106,005	$ 9,654,778
Common shares, shares outstanding (in shares)	52,701,111
Number of co-founders | co-founder			3
Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation expense, options | $			$ 4,200,000
Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense | $			$ 1,204,952	364,381
Weighted average period of recognition			1 year 9 months
Expiration period	10 years
Unrecognized compensation expense | $			$ 3,300,000
Share-Based Payment Arrangement, Tranche Three | Equity Incentive Plan | Share-Based Payment Arrangement, Employee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
Share-Based Payment Arrangement, Tranche Four | Equity Incentive Plan | Share-Based Payment Arrangement, Employee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
Share-Based Payment Arrangement, Tranche Two | Equity Incentive Plan | Share-Based Payment Arrangement, Nonemployee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	12 months
Share-Based Payment Arrangement, Tranche Two | Equity Incentive Plan | Share-Based Payment Arrangement, Employee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
Share-Based Payment Arrangement, Tranche One | Equity Incentive Plan | Share-Based Payment Arrangement, Nonemployee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period	3 years
Share-based compensation arrangement by share-based payment award, number of vesting installments | installment	3
Share-Based Payment Arrangement, Tranche One | Equity Incentive Plan | Share-Based Payment Arrangement, Employee
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
MoonLake AG Restricted Founder Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense | $			$ 1,574,300	4,840,608
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense | $			3,352,885	3,910,076
Unrecognized share-based compensation expense, non-option awards | $			$ 6,200,000
Weighted average period of recognition			2 years 18 days
ESPP | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average period of recognition			2 years 5 months 12 days
ESPP | Share-Based Payment Arrangement, Tranche Three
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESPP | Share-Based Payment Arrangement, Tranche Four
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESPP | Share-Based Payment Arrangement, Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESPP | Share-Based Payment Arrangement, Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESOP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense | $			$ 973,868	$ 539,713
ESOP | Share-Based Payment Arrangement, Tranche Three | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESOP | Share-Based Payment Arrangement, Tranche Four | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESOP | Share-Based Payment Arrangement, Tranche Two | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
ESOP | Share-Based Payment Arrangement, Tranche One | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage			25%
MoonLake AG
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Reverse vesting percentage		90%				90%
Common shares, shares outstanding (in shares)		110,000				110,000
MoonLake AG | MoonLake AG Restricted Founder Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares, shares outstanding (in shares)		99,000				99,000
Vesting percentage		4.166%
Vesting period		2 years
Nominal value (CHF per share) | SFr / shares						SFr 0.10
Common Class C
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares, shares outstanding (in shares)			2,505,476	13,723,511
Common shares, par value (USD per share) | $ / shares			$ 0.0001	$ 0.0001
Common Class C | MoonLake AG
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares, shares outstanding (in shares)		3,700,257				3,700,257
Common Class C | MoonLake AG | MoonLake AG Restricted Founder Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares, shares outstanding (in shares)		3,330,231				3,330,231
Common Class A
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares, shares outstanding (in shares)			60,466,453	38,977,600
Common shares, par value (USD per share) | $ / shares		$ 0.0001	$ 0.0001	$ 0.0001
Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares issuable (in shares)			11,079
Common shares, shares outstanding (in shares)					12,161,331
Common Stock | Common Class C
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares issuable (in shares)			372,683
Common shares, shares outstanding (in shares)			2,505,476	13,723,511
Common shares, par value (USD per share) | $ / shares			$ 0.0001
Common Stock | Common Class A
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common shares, shares outstanding (in shares)			60,466,453	38,977,600
Common shares, par value (USD per share) | $ / shares			$ 0.0001

Share-based Compensation - Shar

Share-based Compensation - Share-based Compensation Expense By Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	$ 7,106,005	$ 9,654,778
Research and Development Expense
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	1,524,715	954,379
General and Administrative Expense
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	5,581,290	8,700,399
Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	1,204,952	364,381
MoonLake AG Restricted Founder Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	1,574,300	4,840,608
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	3,352,885	3,910,076
ESOP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation expense	$ 973,868	$ 539,713

Share-based Compensation - Assu

Share-based Compensation - Assumptions (Details)	12 Months Ended
	Dec. 31, 2023 $ / shares	Dec. 31, 2022 $ / shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2022 SFr / shares	Dec. 31, 2021 SFr / shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Enterprise value | $			$ 360,000,000
Fully diluted shares (in shares) | shares			1,070,196
Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Estimated fair value of the option on the grant date using Black-Scholes model (in dollars per share)	$ 25.58	$ 8.25
Exercise price (in dollars per share)	$ 37.22	$ 12.25
Expected term of the award	6 years	6 years
Expected volatility of the share price	75%	75%
Risk-free interest rate	4%	3%
Expected dividend rate	0%	0%
MoonLake AG Restricted Founder Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Estimated fair value per share of Restricted Founder Shares on the grant date (in dollars per share)			$ 49
Estimated fair value of Restricted Founder Shares on the resignation date of one of the co-founders of MoonLake AG (in dollars per share)			$ 336.39
Purchase price (in CHF per share) | SFr / shares					SFr 0.1
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Estimated fair value per share of Restricted Founder Shares on the grant date (in dollars per share)		$ 336.39
Purchase price (in CHF per share) | SFr / shares				SFr 0.1
ESOP | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Estimated fair value of the option on the grant date using Black-Scholes model (in dollars per share)	$ 25.5	4.21
Exercise price (in dollars per share)	$ 37.1	$ 3.64
Expected term of the award	6 years	6 years
Expected volatility of the share price	75%	75%
Risk-free interest rate	4%	3%
Expected dividend rate	0%	0%

Share-based Compensation - Awar

Share-based Compensation - Awarded and Granted (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Awards outstanding beginning balance (in shares)	180,000	0
Awards granted (in shares)	132,400	180,000
Awards outstanding ending balance (in shares)	312,400	180,000
Awards exercisable (in shares)	60,000	0
MoonLake AG Restricted Founder Shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Awards outstanding, beginning balance (in shares)	1,110,078	4,440,309
Awards vested (in shares)	(1,110,078)	(3,330,231)
Awards outstanding, ending balance (in shares)	0	1,110,078
ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Awards outstanding, beginning balance (in shares)	2,237,915	1,060,561
Awards granted (in shares)	0	1,177,354
Awards vested (in shares)	(1,607,425)	(307,794)
Awards outstanding, ending balance (in shares)	2,237,915	2,237,915
ESOP | Employee Stock Option Plan (ESOP)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Awards outstanding beginning balance (in shares)	466,769	224,033
Awards granted (in shares)	133,446	242,736
Awards forfeited (in shares)	(15,137)
Awards outstanding ending balance (in shares)	585,078	466,769
Awards exercisable (in shares)	219,223

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Effective income tax rate	(0.30%)	0.10%
Deferred tax assets, gross	$ 11,334,793	$ 11,736,269
Deferred tax assets, valuation allowance	11,278,931	$ 11,736,269
Operating loss carryforwards	56,600,000
Expiration in 2028
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	12,600,000
Expiration in 2029
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 44,000,000

Income Taxes - Summary of Net I

Income Taxes - Summary of Net Income (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Switzerland	$ (43,469,946)	$ (62,115,251)
Foreign	(514,783)	(2,354,434)
Income (loss) attributable to parent, before tax	$ (43,984,729)	$ (64,469,685)

Income Taxes - Statutory Tax Pe

Income Taxes - Statutory Tax Percent (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Statutory income tax rate	11.80%	11.90%
Effect of income taxed at different rates	(0.40%)	0%
Change in prior year estimates	(0.50%)	0.10%
Utilization of unrecognized losses	0.60%	0%
Change in valuation allowance	0.50%	(10.00%)
Non-deductible expense	(12.30%)	(1.40%)
Other	0%	(0.50%)
Effective income tax rate	(0.30%)	0.10%

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Intangible assets	$ 4,493,559	$ 4,492,435
Defined benefit plan	69,173	33,451
Lease liabilities	56,527	0
Net operating loss carry forward	6,715,534	7,210,383
Total deferred tax assets	11,334,793	11,736,269
Operating lease right-of-use assets	(55,862)	0
Total deferred tax liabilities	(55,862)	0
Total deferred tax assets (net)	11,278,931	11,736,269
Valuation allowance	(11,278,931)	(11,736,269)
Total deferred tax (net)	$ 0	$ 0

Commitment and Contingencies (D

Commitment and Contingencies (Details) € in Millions, $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 12, 2023	Aug. 31, 2021
Other Commitments [Line Items]
Total commitments not yet recognized	$ 44.2
Prepaid Expenses, Noncurrent
Other Commitments [Line Items]
Total commitments not yet recognized	$ 8.4
Office Lease
Other Commitments [Line Items]
Lessee, operating lease, term of contract	3 years	3 years	3 years	3 years
License | SLK Program
Other Commitments [Line Items]
Revenue remaining performance obligation additional variable consideration amount	$ 331.3	€ 299.6
Variable consideration amount	$ 8.1	€ 7.5

Segment Information and Geogr_3

Segment Information and Geographic Data (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Long-lived assets	$ 3,949,345	$ 331,969
Switzerland
Segment Reporting Information [Line Items]
Long-lived assets	507,392	331,969
United Kingdom
Segment Reporting Information [Line Items]
Long-lived assets	2,704,555	0
Portugal
Segment Reporting Information [Line Items]
Long-lived assets	$ 737,398	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Millions			1 Months Ended		2 Months Ended	12 Months Ended
	Jan. 02, 2024	Oct. 04, 2021	Dec. 31, 2023	May 31, 2023	Feb. 29, 2024	Dec. 31, 2023	Dec. 31, 2022
Subsequent Event [Line Items]
Sale of stock (in shares)			525,924	544,894
Sale of stock, consideration received on transaction			$ 31.7	$ 15.2
Subsequent Event | August 2023 Sales Agreement
Subsequent Event [Line Items]
Sale of stock (in shares)					914,828
Sale of stock, consideration received on transaction					$ 53.3
Proceeds from issuance of common stock					$ 85
Common Class A
Subsequent Event [Line Items]
Sale of stock (in shares)		11,700,000				10,270,818
Common Stock
Subsequent Event [Line Items]
Conversion and transfer of shares between classes (in shares)						333,486	61,000
Common Stock | Subsequent Event
Subsequent Event [Line Items]
Conversion and transfer of shares between classes (in shares)	44,394
Common Stock | Common Class C
Subsequent Event [Line Items]
Conversion and transfer of shares between classes (in shares)						(11,218,035)	2,051,961
Common Stock | Common Class C | Subsequent Event
Subsequent Event [Line Items]
Conversion and transfer of shares between classes (in shares)	1,493,356
Common Stock | Common Class A
Subsequent Event [Line Items]
Conversion and transfer of shares between classes (in shares)						11,218,035	2,051,961
Common Stock | Common Class A | Subsequent Event
Subsequent Event [Line Items]
Conversion and transfer of shares between classes (in shares)	1,493,356