Atai Life Sciences (ATAI) 10-Q/A 14 Nov 24 2024 Q3 Quarterly report (amended) Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2024	Nov. 05, 2024
Cover [Abstract]
Document Type	10-Q/A
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Trading Symbol	ATAI
Title of 12(b) Security	Common shares, par value €0.10 per share
Security Exchange Name	NASDAQ
Entity Registrant Name	ATAI Life Sciences N.V.
Entity Central Index Key	0001840904
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Securities Act File Number	001-40493
Entity Incorporation, State or Country Code	P7
Document Transition Report	false
Entity Address, Address Line One	ATAI Life Sciences N.V.
Entity Address, Address Line Two	Wallstraße 16
Entity Address, City or Town	Berlin
City Area Code	49 89
Local Phone Number	2153 9035
Entity Address, Country	DE
Entity Address, Postal Zip Code	10179
Entity Tax Identification Number	00-0000000
Entity Common Stock, Shares Outstanding		167,802,396

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 29,963	$ 45,034
Securities carried at fair value	55,957	109,223
Short term restricted cash for other investments	15,000	0
Committed investment funds	0	25,000
Prepaid expenses and other current assets	7,454	5,830
Short term notes receivable - related party, net	5,700	505
Total current assets	114,074	185,592
Property and equipment, net	865	981
Operating lease right-of-use asset, net	1,032	1,223
Other Investments held at fair value	45,227	89,825
Other investments	33,893	1,838
Long term notes receivable - related parties, net	0	97
Convertible notes receivable - related party	0	11,202
Other assets	2,428	2,720
Total assets	197,519	293,478
Current liabilities:
Accounts payable	4,880	4,589
Accrued liabilities	11,953	15,256
Current portion of lease liability	257	275
Short term convertible promissory notes and derivative liability - related party	925	0
Short term convertible promissory notes and derivative liability	1,481	0
Other current liabilities	147	0
Total current liabilities	19,643	20,120
Contingent consideration liability - related parties	650	620
Contingent consideration liability	1,388	1,637
Noncurrent portion of lease liability	808	990
Convertible promissory notes and derivative liability - related party	0	164
Convertible promissory notes and derivative liability	0	2,666
Long-term debt, net	20,336	15,047
Other liabilities	8,378	7,918
Total liabilities	51,203	49,162
Commitments and contingencies (Note 16)
Stockholders' equity:
Common stock, 0.10 par value ($0.11 and $0.12 par value at September 30, 2024 and December 31, 2023, respectively); 750,000,000 shares authorized at September 30, 2024 and December 31, 2023, respectively; 167,818,316 and 166,026,396 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively	18,770	18,573
Additional paid-in capital	808,355	794,787
Accumulated other comprehensive loss	(20,156)	(19,460)
Accumulated deficit	(661,249)	(550,938)
Total stockholders' equity attributable to ATAI Life Sciences N.V. stockholders	145,720	242,962
Noncontrolling interests	596	1,354
Total stockholders' equity	146,316	244,316
Total liabilities and stockholders' equity	$ 197,519	$ 293,478

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)	Sep. 30, 2024 € / shares shares	Sep. 30, 2024 $ / shares shares	Dec. 31, 2023 € / shares shares	Dec. 31, 2023 $ / shares shares
Common Stock, Par or Stated Value Per Share | (per share)	€ 0.1	$ 0.11	€ 0.1	$ 0.12
Common stock, shares authorized	750,000,000	750,000,000	750,000,000	750,000,000
Common stock, shares, issued	167,818,316	167,818,316	166,026,396	166,026,396
Common stock, shares, outstanding	167,818,316	167,818,316	166,026,396	166,026,396

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
License revenue	$ 40	$ 87	$ 313	$ 296
Operating expenses:
Research and development	12,377	13,290	36,513	48,047
General and administrative	10,265	13,631	36,226	44,159
Total operating expenses	22,642	26,921	72,739	92,206
Loss from operations	(22,602)	(26,834)	(72,426)	(91,910)
Other income (expense), net:
Interest income	160	612	585	1,191
Interest expense	(783)	(686)	(2,172)	(1,965)
Benefit from research and development tax credit	31	0	617	0
Change in fair value of assets and liabilities, net	(1,964)	70,810	(33,764)	72,411
Foreign exchange gain (loss), net	770	253	676	(593)
Other expense, net	(2,075)	(308)	(2,737)	(100)
Total other income (expense), net	(3,861)	70,681	(36,795)	70,944
Net income (loss) before income taxes	(26,463)	43,847	(109,221)	(20,966)
Benefit from (provision for) income taxes	178	(238)	163	(588)
Losses from investments in equity method investees, net of tax	(26)	(238)	(2,000)	(3,199)
Net income (loss)	(26,311)	43,371	(111,058)	(24,753)
Net loss attributable to noncontrolling interests	(25)	(873)	(747)	(2,821)
Net income (loss) attributable to ATAI Life Sciences N.V. stockholders	$ (26,286)	$ 44,244	$ (110,311)	$ (21,932)
Net income (loss) per share attributable to ATAI Life Sciences N.V. stockholder - basic	$ (0.16)	$ 0.28	$ (0.69)	$ (0.14)
Net income (loss) per share attributable to ATAI Life Sciences N.V. stockholders - diluted	$ (0.16)	$ 0.25	$ (0.69)	$ (0.14)
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. stockholders - basic	160,621,817	155,792,490	159,973,201	155,793,601
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. stockholders - diluted	160,621,817	177,565,973	159,973,201	155,793,601

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (26,311)	$ 43,371	$ (111,058)	$ (24,753)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	(985)	1,709	(696)	2,593
Comprehensive income (loss)	(27,296)	45,080	(111,754)	(22,160)
Net loss attributable to noncontrolling interests	(25)	(873)	(747)	(2,821)
Foreign currency translation adjustments, net of tax attributable to noncontrolling interests	(22)	22	(11)	31
Comprehensive loss attributable to noncontrolling interests	(47)	(851)	(758)	(2,790)
Comprehensive gain (loss) attributable to ATAI Life Sciences N.V. stockholders	$ (27,249)	$ 45,931	$ (110,996)	$ (19,370)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital	Share Subscriptions Receivable	Accumulated Other Comprehensive Loss	Accumulated Deficit	Total Stockholders' Equity Attributable to ATAI Life Sciences N.V. Stockholders	Noncontrolling Interests
Beginning Balance at Dec. 31, 2022	$ 265,766	$ 18,562	$ 774,092	$ (24)	$ (21,702)	$ (510,188)	$ 260,740	$ 5,026
Beginning Balance, Shares at Dec. 31, 2022		165,935,914
Issuance of shares upon exercise of stock options	181	$ 9	172				181
Issuance of shares upon exercise of stock options, shares		74,562
Settlement of issuance of shares upon exercise of stock options	24			24			24
Stock-based compensation expense	8,662		8,662				8,662
Adjustment to accumulated deficit (pursuant to adoption of ASU 2016-13)	(526)					(526)	(526)
Foreign currency translation adjustment, net of tax	887				879		879	8
Net income (loss)	(34,354)					(33,135)	(33,135)	(1,219)
Ending Balance at Mar. 31, 2023	240,640	$ 18,571	782,926	0	(20,823)	(543,849)	236,825	3,815
Ending Balance, Shares at Mar. 31, 2023		166,010,476
Stock-based compensation expense	8,762		8,762				8,762
Foreign currency translation adjustment, net of tax	6				5		5	1
Net income (loss)	(33,771)					(33,042)	(33,042)	(729)
Ending Balance at Jun. 30, 2023	215,637	$ 18,571	791,688	0	(20,818)	(576,891)	212,550	3,087
Ending Balance, Shares at Jun. 30, 2023		166,010,476
Adjustment to additional paid in capital upon acquiring additional interest in variable interest entity	(480)		(480)				(480)
Stock-based compensation expense	8,253		8,253				8,253
Foreign currency translation adjustment, net of tax	1,731				1,709		1,709	22
Net income (loss)	43,371					44,244	44,244	(873)
Ending Balance at Sep. 30, 2023	268,512	$ 18,571	799,461	$ 0	(19,109)	(532,647)	266,276	2,236
Ending Balance, Shares at Sep. 30, 2023		166,010,476
Beginning Balance at Dec. 31, 2023	244,316	$ 18,573	794,787		(19,460)	(550,938)	242,962	1,354
Beginning Balance, Shares at Dec. 31, 2023		166,026,396
Issuance of shares upon restricted stock units vest		$ 27	(27)
Issuance of shares upon restricted stock units vest, shares		248,030
Stock-based compensation expense	5,760		5,760				5,760
Foreign currency translation adjustment, net of tax	559				535		535	24
Net income (loss)	(27,378)					(26,713)	(26,713)	(665)
Ending Balance at Mar. 31, 2024	223,257	$ 18,600	800,520		(18,925)	(577,651)	222,544	713
Ending Balance, Shares at Mar. 31, 2024		166,274,426
Beginning Balance at Dec. 31, 2023	244,316	$ 18,573	794,787		(19,460)	(550,938)	242,962	1,354
Beginning Balance, Shares at Dec. 31, 2023		166,026,396
Ending Balance at Sep. 30, 2024	146,316	$ 18,770	808,355		(20,156)	(661,249)	145,720	596
Ending Balance, Shares at Sep. 30, 2024		167,818,316
Beginning Balance at Mar. 31, 2024	223,257	$ 18,600	800,520		(18,925)	(577,651)	222,544	713
Beginning Balance, Shares at Mar. 31, 2024		166,274,426
Issuance of shares upon exercise of stock options	326	$ 30	296				326
Issuance of shares upon exercise of stock options, shares		276,531
Issuance of shares upon restricted stock units vest		$ 135	(135)
Issuance of shares upon restricted stock units vest, shares		1,221,033
Adjustment to additional paid in capital upon acquiring additional interest in variable interest entity	(115)		(115)				(115)
Stock-based compensation expense	6,282		6,282				6,282
Adjustment to additional paid in capital upon debt modification	(3,590)		(3,590)				(3,590)
Foreign currency translation adjustment, net of tax	(259)				(246)		(246)	(13)
Net income (loss)	(57,369)					(57,312)	(57,312)	(57)
Ending Balance at Jun. 30, 2024	168,533	$ 18,765	803,259		(19,171)	(634,963)	167,890	643
Ending Balance, Shares at Jun. 30, 2024		167,771,990
Issuance of shares upon exercise of stock options	55	$ 5	50				55
Issuance of shares upon exercise of stock options, shares		46,326
Stock-based compensation expense	5,046		5,046				5,046
Foreign currency translation adjustment, net of tax	(1,007)				(985)		(985)	(22)
Net income (loss)	(26,311)					(26,286)	(26,286)	(25)
Ending Balance at Sep. 30, 2024	$ 146,316	$ 18,770	$ 808,355		$ (20,156)	$ (661,249)	$ 145,720	$ 596
Ending Balance, Shares at Sep. 30, 2024		167,818,316

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities
Net loss	$ (111,058)	$ (24,753)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization of long term assets	248	218
Noncash lease expense	202	297
Amortization of debt discount	327	272
Stock-based compensation expense	17,088	25,677
Noncash change in the fair value of assets and liabilities, net	35,965	(72,411)
Loss on sale of investment held at fair value	2,075	0
Unrealized foreign exchange (gain) loss	(789)	555
Losses from investments in equity method investees, net of tax	2,000	3,199
Other income (expenses)	965	(42)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,599)	6,716
Accounts payable	261	3,096
Accrued liabilities	(3,827)	(4,980)
Net cash used in operating activities	(58,142)	(62,156)
Cash flows from investing activities
Proceeds from sale and maturities of securities carried at fair value	54,270	130,363
Proceeds from sale of other investment held at fair value	16,093	0
Cash paid for securities carried at fair value	0	(177,047)
Cash paid for investments	(10,000)	0
Cash paid for short term convertible notes receivable and warrant - related party	(2,000)	0
Cash paid for short term notes receivable - related party	(5,745)	0
Cash paid for long term notes receivable - related parties, net	0	(3,000)
Cash paid for convertible notes receivable - related party	0	(1,497)
Cash paid for other investments held at fair value	0	(724)
Cash paid for additional interest in variable interest entity	0	(480)
Proceeds from sale of other investment	0	486
Cash paid for capitalized internal-use software development costs	(6)	(322)
Cash paid for property and equipment	0	(251)
Net cash provided by (used in) investing activities	52,612	(52,472)
Cash flows from financing activities
Proceeds from debt financing	5,000	0
Proceeds from issuance of shares upon exercise of stock options	381	206
Financing costs paid	(161)	(100)
Net cash provided by financing activities	5,220	106
Effect of foreign exchange rate changes on cash	239	401
Net decrease in cash, cash equivalents and restricted cash	(71)	(114,121)
Cash, cash equivalents and restricted cash - beginning of the period	45,034	190,613
Cash, cash equivalents and restricted cash - end of the period	44,963	76,492
Supplemental disclosures:
Cash paid for taxes	376	1,475
Cash paid for interest	1,654	1,428
Supplemental disclosures of noncash investing and financing information:
Noncash exchange of convertible promissory note modification	3,586	0
Right of use asset obtained in exchange for operating lease liabilities	0	1,356
Noncash commitment for debtor-in-possession loan	147	0
Noncash consideration for variable interest deconsolidation	$ 115	$ 0

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (26,286)	$ 44,244	$ (110,311)	$ (21,932)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Organization and Description of

Organization and Description of Business	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Or ganization and Description of Business ATAI Life Sciences N.V. (“atai" or the "Company"), headquartered in Berlin, Germany is the parent company of ATAI Life Sciences AG and, along with its subsidiaries, is a clinical-stage biopharmaceutical company aiming to transform the treatment of mental health disorders. atai was founded in 2018 as a response to the significant unmet need and lack of innovation in the mental health treatment landscape and is dedicated to efficiently developing innovative therapeutics to treat depression, anxiety, addiction, and other mental health disorders. By pooling resources and best practices, atai aims to responsibly accelerate the development of new medicines to achieve clinically meaningful and sustained behavioral change in mental health patients. The Company is subject to risks and uncertainties common to clinical stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, third-party clinical research organizations and manufacturers, protection of proprietary intellectual property and technology, compliance with government regulations and the ability to secure additional capital to fund operations. Therapeutic candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s therapeutic development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from sales. The Company operates and manages the business as one reportable segment, which is the business of identifying and advancing mental health innovations. The Company has determined that its chief executive officer is the chief operating decision maker (“CODM”). The CODM reviews consolidated operating expenses to make decisions about allocating resources or capital to specific compounds or projects in line with overall Company’s strategies and goals. The Company operates in two geographic regions primarily in the United States and Germany. Liquidity and Going Concern The Company has incurred significant losses and negative cash flows from operations since its inception. As of September 30, 2024 , the Company had cash and cash equivalents of $ 30.0 million, restricted cash of $ 15.0 million, and short-term securities of $ 56.0 million and its accumulated deficit was $ 661.2 million. The Company has historically financed its operations through the sale of equity securities, debt financings, sale of convertible notes and revenue generated from licensing and collaboration arrangements. The Company has not generated any revenues to date from the sale of its product candidates and does not anticipate generating any revenues from the sale of its product candidates unless and until it successfully completes development and obtains regulatory approval to market its product candidates. The Company currently expects that its existing cash and cash equivalents and short-term securities as of September 30, 2024 will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next 12 months from the date the unaudited condensed consolidated financial statements are issued.

Basis of Presentation, Consolid

Basis of Presentation, Consolidation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation, Consolidation and Summary of Significant Accounting Policies	2. Basis of Presentation, Consolidation and Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and follow the requirements of the United States Securities and Exchange Commission (“SEC”) for interim financial reporting. Accordingly, these unaudited condensed consolidated financial statements do not include all of the information and disclosures required by U.S. GAAP for complete financial statements as certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on March 28, 2024. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial position, its results of operations and comprehensive loss, and its cash flows for the periods presented. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other future annual or interim period. Any reference in these notes to applicable accounting guidance is meant to refer to the authoritative U.S. GAAP included in the Accounting Standards Codification (“ASC”), and Accounting Standards Update (“ASU”) issued by the Financial Accounting Standards Board (“FASB”). Reclassifications Certain reclassifications were made to prior period amounts in the unaudited condensed consolidated financial statements and accompanying notes to conform with current year presentation in order to consolidate and simplify the disclosures of changes in assets and liabilities held at fair value. Consolidation The Company's unaudited condensed consolidated financial statements include the accounts of atai and its subsidiaries. All intercompany balances and transactions have been eliminated in the consolidation. The Company's policy is to consolidate all entities that it controls by ownership of a majority of the outstanding voting stock. In addition, entities that meet the definition of a variable interest entity (“VIE”) for which atai is the primary beneficiary are consolidated. The primary beneficiary is the party who has the power to direct the activities of a VIE that most significantly impact the entity’s economic performance and who has an obligation to absorb losses of the entity or a right to receive benefits from the entity that could potentially be significant to the entity. For consolidated entities that are less than wholly-owned, the third-party’s holding of equity interest is presented as Noncontrolling interests in the Company's unaudited condensed consolidated balance sheets and unaudited condensed consolidated statements of stockholders' equity. The portion of net earnings attributable to the noncontrolling interests is presented as Net loss attributable to noncontrolling interests in the Company's unaudited condensed consolidated statements of operations. Ownership interests in entities over which the Company has significant influence, but not a controlling financial interest, are accounted for under either the alternative measurement under ASC 321 or as an equity method investment. Investments eligible for the measurement alternative under ASC 321 are carried at its initial cost, with remeasurements to fair value upon impairment or upon a price change observed in an orderly transaction of the same or similar investment of the same issuer . For equity method investments where the Company has not elected the fair value option, it records gains (losses) from investments in equity method investees, net of tax, for its proportionate share of the underlying company’s net results until the investment balance is adjusted to zero. If the Company makes subsequent additional investments in that same company, it may record additional gains (losses) based on changes to its investment basis and also may record additional income (loss) in equity method investments. If the Company has elected the fair value option for an equity investment, the fair value of the investment will be recorded upon acquisition and any changes in fair value will be recorded as a component of other income (expense), net. Significant Accounting Policies During the nine months ended September 30, 2024, there were no significant changes to the Company’s significant accounting policies as described in the Company’s audited consolidated financial statements as of and for the year ended December 31, 2023 exc ept as described below. Restricted Cash The Company maintains certain cash balances restricted as to withdrawal or use. Restricted cash assets as of September 30, 2024 are for the sole purpose of purchasing additional Series C Shares in Beckley Psytech Limited. See Note 5 for further information. Recently Adopted Accounting Pronouncements ASU 2016-13 Financial Instruments - Credit Losses In June 2016, the FASB issued ASU 2016-13, Financial Instruments — Credit Losses. This guidance requires immediate recognition of management’s estimates of current expected credit losses. Under the prior model, losses were recognized only when losses were deemed probable. The new model is applicable to most financial assets and certain other instruments that are not measured at fair value through net income. The Company utilizes an undiscounted probability-of-default (“PD”) and loss-given-default (“LGD”) method for estimating credit losses on its assets pool, which is comprised of loans to other companies. Under the PD and LGD method, the expected credit loss percentage (or “loss rate”) is calculated as the probability of default (i.e., the probability the asset will default within the given time frame) multiplied by the loss given default (i.e., the percentage of the asset not expected to be collected because of default). To implement the PD and LGD method, the Company utilizes readily observable market information from term-matched public debt to derive market implied current expected credit losses (“MICECL”) grouped by Standard & Poor’s (“S&P”) credit rating scale. The MICECL framework considers risk characteristics of assets pool based on publicly available or estimated S&P credit ratings to calculate an appropriate credit loss reserve for the pool or group of assets. ASU 2016-13 requires a cumulative effect adjustment to the statement of financial position as of the beginning of the first reporting period in which it is effective. On January 1, 2023, the Company adopted this guidance and applied a modified-retrospective transition approach through a cumulative-effect adjustment to retained earnings upon adoption. At transition, the new accounting guidance’s adoption resulted in an increase to accumulated deficit of $ 0.5 million, net of tax attributable to an increase in the allowance for credit losses related to its l ong-term notes receivable - related parties. Further, the FASB issued ASU 2019-04, ASU 2019-05, ASU 2019-11, ASU 2020-03 and ASU 2022-02 to provide additional clarification and guidance on the credit losses standard. The Company adopted ASU 2019-04, ASU 2019-05, ASU 2019-11, ASU 2020-03 and ASU 2022-02 on January 1, 2023. The adoption of these standards did not have a material impact on the Company’s consolidated financial statements or disclosures. Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standard Board ("FASB") issued new guidance designed to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant expenses per segment. The guidance is effective for all fiscal years beginning after December 15, 2023, and for interim periods beginning after December 15, 2024. The new standard must be adopted on a retrospective basis and early adoption is permitted. The Company is not early adopting the standard. We are currently evaluating this guidance to determine its impact on our consolidated financial statements. In December 2023, the FASB issued new guidance designed to improve income tax disclosure requirements, primarily through increased disaggregation disclosures within the effective tax rate reconciliation as well as enhanced disclosures on income taxes paid. The guidance is effective for all fiscal years beginning after December 15, 2024. The new standard can be adopted on a prospective basis with an option to be adopted retrospectively and early adoption is permitted. The Company is not early adopting the standard. We are currently evaluating this guidance to determine its impact on our consolidated financial statements. In November 2024, the FASB issued new guidance designed to improve income statement expense disclosures, primarily by requiring new financial statement disclosures in tabular format and disaggregating information about prescribed categories underlying any relevant income statement captions. The standard is effective for fiscal years beginning after December 15, 2026 and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. Upon adoption, the new standard may be applied prospectively or retrospectively. The Company is currently evaluating the impact that the adoption may have on its disclosures in its condensed consolidated financial statements.

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2024
Business Combinations [Abstract]
Acquisitions and Dispositions	3. Acquisitions and Dispositions 2023 Dispositions Psyber, Inc. In October 2023, the Company entered into a Framework Agreement with the founders of Psyber, Inc. ("Psyber Founders") through which the Company transferred its equity interest in Psyber, Inc. ("Psyber") to the Founders in exchange for certain intellectual property. As a result of the disposition, the Company ceased having controlling financial interest in Psyber. The Company determined that it was no longer the primary beneficiary, no longer had the power to direct the significant activities of Psyber, and accordingly, deconsolidated Psyber. T he Company derecognized all of Psyber's assets and liabilities, with the exception of the retained intellectual property, from its consolidated balance sheet and recognized a loss of $ 0.3 million, which was reported as Loss on deconsolidation of a variable interest entity, a component of other income, net in the consolidated statement of operations for the year ended December 31, 2023. The Company concluded that the decision to deconsolidate Psyber, which was based on resource capital allocation decisions, did not represent a significant strategic shift that would have a material effect on the Company's operations and financial results. Therefore, the Company did not present the results of Psyber prior to deconsolidation as discontinued operations in its consolidated statements of operations for the year ended December 31, 2023. TryptageniX, Inc. In December 2023, the Company finalized and entered into a Framework Agreement with CB Therapeutics, Inc. ("CBT") through which the Company transferred its equity interest in TryptageniX Inc. ("TryptageniX") to CBT in exchange for certain intellectual property and an Amended and Restated Development Services and Exclusive License Agreement. As a result of the disposition, the Company ceased having controlling financial interest in TryptageniX. The Company determined that it was no longer the primary beneficiary, no longer had the power to direct the significant activities of TryptageniX, and accordingly, deconsolidated TryptageniX. The Company derecognized all of TryptageniX 's assets and liabilities from its consolidated balance sheet, and recognized a gain of $ 0.4 million, which was reported as Gain on deconsolidation of a variable interest entity, a component of other income, net in the consolidated statement of operations for the year ended December 31, 2023. The Company concluded that the decision to deconsolidate TryptageniX, which was based on resource capital allocation decisions, did not represent a significant strategic shift that would have a material effect on the Company's operations and financial results. Therefore, the Company did not present the results of TryptageniX prior to deconsolidation as discontinued operations in its consolidated statements of operations for the year ended December 31, 2023.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	4. Variable Interest Entities Consolidated VIEs At each reporting period, the Company reassesses whether it remains the primary beneficiary for Variable Interest Entities (“VIEs”) consolidated under the VIE model. The entities consolidated by the Company are comprised of wholly and partially owned entities for which the Company is the primary beneficiary under the VIE model as the Company has (i) the power to direct the activities that most significantly impact the VIE’s economic performance and (ii) the obligation to absorb losses that could potentially be significant to the VIE, or the right to receive benefits from the VIE that could potentially be significant to the VIE. The results of operations of the consolidated entities are included within the Company’s unaudited condensed consolidated financial statements from the date of acquisition to September 30, 2024. As of September 30, 2024 and December 31, 2023, the Company has accounted for the following consolidated investments as VIEs: Consolidated Entities Relationship as of Relationship as of Date Control Obtained Ownership % September 30, 2024 Ownership % December 31, 2023 Perception Neuroscience Holdings, Inc. Controlled VIE Controlled VIE November 2018 59.2 % 59.2 % Kures, Inc. Controlled VIE Controlled VIE August 2019 64.5 % 64.5 % Recognify Life Sciences, Inc. Controlled VIE Controlled VIE November 2020 51.9 % 51.9 % PsyProtix, Inc. Wholly-Owned Subsidiary Controlled VIE February 2021 100.0 % 75.0 % As of September 30, 2024 and December 31, 2023, the assets of the consolidated VIEs can only be used to settle the obligations of the respective VIEs. The liabilities of the consolidated VIEs are obligations of the respective VIEs and their creditors have no recourse to the general credit or assets of atai. PsyProtix, Inc. On February 3, 2021, PsyProtix, Inc. ("PsyProtix") was created as a joint venture between the Company and Chymia (the “Founders”), with the intent of PsyProtix becoming a newly formed corporate subsidiary of ATAI. PsyProtix was created for the purpose of exploring and developing a metabolomics-based precision psychiatry approach. Based on the Company's assessment of the transaction at the time of acquisition, the Company concluded that PsyProtix was not a business and accounted for the Company's investment as an initial consolidation of a VIE that is not a business under ASC 810. In April 2024, the Company and Chymia entered into a Framework Agreement which resulted in the Company's acquisition of Chymia's 25 % equity ownership of PsyProtix (the “Stock Transfer”). As a result of the Stock Transfer, the Company owned 100 % of the outstanding common stock of PsyProtix, and PsyProtix became a wholly owned subsidiary of the Company. The Stock Transfer was accounted for as an equity transaction with no gain or loss recognized. The difference between the carrying amount of Chymia's non-controlling interest and the note receivable forgiven in the acquisition of the additional equity interest was recorded as a reduction in additional paid-in capital in the unaudited condensed consolidated balance sheets and unaudited condensed consolidated statements of stockholders' equity. The following table presents the assets and liabilities (excluding intercompany balances that were eliminated in consolidation) for all VIEs as of September 30, 2024 (in thousands): Perception Kures Recognify Assets: Current assets: Cash $ 89 $ 26 $ 2,508 Accounts receivable 313 — — Prepaid expenses and other current assets 5 37 62 Total current assets 407 63 2,570 Total assets $ 407 $ 63 $ 2,570 Liabilities: Current liabilities: Accounts payable $ 236 $ 375 $ 565 Accrued liabilities 352 174 2,222 Other current liabilities 40 — 3 Total current liabilities 628 549 2,790 Total liabilities $ 628 $ 549 $ 2,790 The following table presents the assets and liabilities (excluding intercompany balances that were eliminated in consolidation) for all consolidated VIEs as of December 31, 2023 (in thousands): Perception Kures Recognify PsyProtix Assets: Current assets: Cash $ 97 $ 257 $ 4,356 $ 35 Accounts receivable 84 — — — Prepaid expenses and other current assets 257 — 450 — Total current assets 438 257 4,806 35 Long-term notes receivable — — — 97 Other assets — — — — Total assets $ 438 $ 257 $ 4,806 $ 132 Liabilities: Current liabilities: Accounts payable $ 31 $ 329 $ 1,926 $ — Accrued liabilities 718 84 609 26 Other current liabilities 12 — 1 — Total current liabilities 761 413 2,536 26 Total liabilities $ 761 $ 413 $ 2,536 $ 26 Noncontrolling Interests The Company recognizes noncontrolling interests related to its consolidated VIEs and provides a roll forward of the noncontrolling interests balance, as follows (in thousands): Perception Kures Recognify Total Balance as of December 31, 2023 $ 428 $ 369 $ 557 $ 1,354 Net loss attributable to noncontrolling interests - preferred ( 100 ) ( 25 ) ( 539 ) ( 665 ) Comprehensive income attributable to noncontrolling interests 17 7 — 24 Balance as of March 31, 2024 $ 345 $ 350 $ 18 $ 713 Net loss attributable to noncontrolling interests - preferred ( 36 ) ( 4 ) ( 18 ) ( 57 ) Comprehensive loss attributable to noncontrolling interests ( 9 ) ( 4 ) — ( 13 ) Balance as of June 30, 2024 $ 300 $ 343 $ — $ 643 Net loss attributable to noncontrolling interests - preferred ( 38 ) 13 — ( 25 ) Comprehensive loss attributable to noncontrolling interests ( 15 ) ( 6 ) — ( 22 ) Balance as of September 30, 2024 $ 247 $ 349 $ — $ 596 Perception Kures Recognify Total Balance as of December 31, 2022 $ 1,731 $ 451 $ 2,844 $ 5,026 Net loss attributable to noncontrolling interests - preferred ( 700 ) ( 93 ) ( 426 ) ( 1,219 ) Comprehensive loss attributable to noncontrolling interests 6 2 — 8 Balance as of March 31, 2023 $ 1,037 $ 360 $ 2,418 $ 3,815 Net loss attributable to noncontrolling interests - preferred ( 266 ) ( 32 ) ( 431 ) ( 729 ) Comprehensive income (loss) attributable to noncontrolling interests ( 1 ) 2 — 1 Balance as of June 30, 2023 $ 770 $ 330 $ 1,987 $ 3,087 Net loss attributable to noncontrolling interests - preferred ( 320 ) 65 ( 618 ) ( 873 ) Comprehensive income (loss) attributable to noncontrolling interests 17 5 — 22 Balance as of September 30, 2023 $ 467 $ 400 $ 1,369 $ 2,236 Non-consolidated VIEs The Company evaluated the nature of its investments in Innoplexus AG (“Innoplexus”), IntelGenx, defined below, and Beckley Psytech Limited (collectively “non-consolidated VIEs”) and determined that the investments are VIEs as of the date of the Company’s initial investment through September 30, 2024.The Company is not the primary beneficiary of the non-consolidated VIEs as it did not have the power to direct the activities that most significantly impact the investments’ economic performance and therefore concluded that it did not have a controlling financial interest in each of the non-consolidated VIEs that would require consolidation as of September 30, 2024 and December 31, 2023. The Company will reevaluate if the investments meet the definition of a VIE upon the occurrence of specific reconsideration events. The Company accounted for these investments under either the equity method, fair value option, or the measurement alternative included within ASC 321 (See Note 5). As of September 30, 2024 , the Company’s maximum exposure for its non-consolidated VIEs was $ 15.0 million of Short-term restricted cash for other investments and $ 5.7 million of Short-term notes receivable - related party, each as shown in the unaudited condensed consolidated balance sheets. As of December 31, 2023 , the Company’s maximum exposure for its non-consolidated VIEs was $ 6.1 million relating to the carrying values in its Other investments, $ 0.1 million of Long-term notes receivable – related party, net and $ 11.2 million of Convertible notes receivable - related party, each as shown in the condensed consolidated balance sheets.

Investments

Investments	9 Months Ended
	Sep. 30, 2024
Cash and Cash Equivalents [Abstract]
Investments	5. Investments Other investments held at fair value COMPASS Pathways plc COMPASS Pathways plc (“COMPASS”) is a mental health care company dedicated to pioneering the development of a new model of psilocybin therapy with its product COMP360. The Company first acquired investments in COMPASS in December 2018 with additional investments through 2021, and accounted for its investment under the equity method until August 2023. In August 2023, COMPASS closed its most recent financing round, in which the Company did not participate, and the Company's ownership interest in COMPASS was reduced to 15.4 %. Following the August 2023 financing, the Company evaluated its ability to continue to exercise significant influence over its investment and determined that it no longer had significant influence and as such will account for its COMPASS investment under ASC 321 at fair value. Any changes in fair value of the Company's investment in COMPASS will be recorded as a Change in fair value of assets and liabilities, net in its unaudited condensed consolidated statements of operations. In September 2024, the Company sold 2,660,000 American Depositary shares ("ADS") of COMPASS at a price of $ 6.05 per ADS in an open market transaction, resulting in net proceeds received of $ 16.1 million. The Company recognized a non-cash loss of $ 2.1 million on the sale during the three months ended September 30, 2024, which is recorded as a component of Other expense, net in its unaudited condensed consolidated statement of operations. Based on quoted market prices, the market value of the Company’s ownership in COMPASS was $ 43.5 million and $ 83.7 million as of September 30, 2024 and December 31, 2023, respectively. The Company has recorded the change in fair value of other investments held at fair value in its unaudited condensed consolidated statements of operations of $ 3.9 million gain and $ 22.0 million loss for the three and nine months ended September 30, 2024, respectively. For the three and nine months ended September 30, 2023 , the Company recorded $ 69.0 million and $ 69.0 million, respectively, of change in fair value of other investments held at fair value in its unaudited condensed consolidated statements of operations. IntelGenx Technologies Corp. IntelGenx Technologies Corp. ("IntelGenx") is a novel drug delivery company focused on the development and manufacturing of novel oral thin film products for the pharmaceutical market. In March 2021, IntelGenx and the Company entered into the Strategic Development Agreement and Purchaser Rights Agreement (“PPA”), (described below). In 2023, IntelGenx and the Company entered into a subscription agreement (described below). Following the initial closing of the IntelGenx SPA (as defined below), the Company held a 25 % voting interest in IntelGenx. Pursuant to the PPA, the Company is entitled to designate a number of directors to the IntelGenx’s board of directors in the same proportion as the shares of common stock held by the Company to the outstanding IntelGenx Common Shares. As of September 30, 2024, the Company maintains significant influence over IntelGenx through the Company's ownership interest in IntelGenx’s equity and its right to noncontrolling representation on IntelGenx's board of directors. In May 2024, IntelGenx announced that its board of directors authorized IntelGenx to bring an application in the Quebec Superior Court to seek protection from creditors under the Companies' Creditors Arrangement Act (“CCAA”) to allow time to review its strategic alternatives. IntelGenx was granted protection pursuant to an initial order ("Initial Order"), which also authorized interim debtor-in-possession financing ("DIP Financing") provided by the Company in order to allow IntelGenx to continue its operations during a restructuring process. Subsequently, IntelGenx obtained approval to implement a sale and investment solicitation process (the "SISP" and the approval, the "SISP Approval Order"). As part of the SISP Approval Order, the Court approved the agreement of purchase and sale between IntelGenx and the Company, solely for the purpose of constituting the “Stalking Horse Bid" under the SISP. The Stalking Horse Bid established a baseline price and deal structure for the solicitation of superior bids from qualified interested parties. In July 2024, and pursuant to the SISP Approval Order, the SISP did not result in alternative superior bids. The Company and IntelGenx completed the purchase and sale transaction in October 2024. Concurrent with the CCAA application, trading in the common shares of IntelGenx on the Toronto Stock Exchange has been halted. As of September 30, 2024, considering relevant facts and circumstances, the Company has estimated a fair value of zero for the various warrants to purchase IntelGenx Common Shares and call option to purchase additional convertible debenture units. Additionally, the Company has estimated the fair value of the various notes receivables with IntelGenx based on the fair value of the underlying collateral of the secured debt, as further described in Note 6 below. 2021 Securities Purchase Agreement In May 2021, IntelGenx and the Company executed a Securities Purchase Agreement (the “IntelGenx SPA”) after obtaining IntelGenx shareholder approval, whereby IntelGenx issued shares of its common stock (the "IntelGenx Common Shares") and warrants to the Company at a price of approximately $ 12.3 million. Each warrant (the “Initial Warrants”) entitles the Company to purchase one share at a price of $ 0.35 per share for a period of three years from the closing of the initial investment in March 2021. Pursuant to the IntelGenx SPA, the Company has the right to purchase (in cash, or in certain circumstances, the Company’s equity) additional units for a period of three years from the closing of the initial investment (the “Additional Unit Warrants”). As of the March 15, 2024 expiration date, the Company had not exercised any of the Initial Warrants or the Additional Unit Warrants, which had a carrying value of zero , resulting in no impact to the unaudited condensed consolidated balance sheet or unaudited condensed consolidated statement of operations. The Company qualified for and elected to account for its investment in the IntelGenx Common Shares under the fair value option. The Company believes that the fair value option better reflects the underlying economics of the IntelGenx Common Shares investment. The Initial Warrants and the Additional Unit Warrants were accounted for at fair value under ASC 321 and recorded in Other investments held at fair value on the consolidated balance sheets. The Company applied a calibrated model and determined that the initial aggregate fair value of its $ 12.3 million investment was equal to the transaction price and recorded the IntelGenx Common Shares at $ 3.0 million, the Initial Warrants at $ 1.2 million and the Additional Unit Warrants at $ 8.2 million on a relative fair value basis resulting in no initial gain or loss recognized in the consolidated statements of operations. The Company recognized subsequent changes in fair value of the IntelGenx Common Shares, Initial Warrants (until exercise or expiration) and Additional Unit Warrants (until exercise or expiration) as a Change in fair value of assets and liabilities, net, a component of other income (expense), net in the consolidated statements of operations. The carrying amount of the IntelGenx Common Shares, Initial Warrants and Additional Unit Warrants was reduced to zero as of December 31, 2021, and remained zero as of September 30, 2024 and December 31, 2023. Accordingly, during the three and nine months ended September 30, 2024 and 2023 , the Company recognized a zero mark-to-market gain/loss for each of the IntelGenx Common Shares, Initial Warrants and Additional Unit Warrants in the unaudited condensed consolidated statements of operations. 2023 Subscription Agreement, as amended In August 2023, IntelGenx and the Company entered into a subscription agreement (the “Subscription Agreement”), under which the Company paid IntelGenx $ 2.2 million for 2,220 convertible debenture units (the "2023 Initial Units"), with each convertible debenture unit consisting of: ( i) $ 1,000 principal amount convertible promissory notes (the “2023 Initial Notes”) bearing interest at a rate of 12.0 % per annum, payable quarterly in arrears beginning September 30, 2023, with all principal and accrued interest convertible into common shares of IntelGenx, at any time from the date that is six months following their issuance up to and including August 31, 2026 at a conversion price equal to $ 0.185 per common share; and (ii) 5,405 common share purchase warrants of IntelGenx (the “2023 Initial Warrants”), each exercisable at an exercise price of $ 0.26 per common share for a period of three years following their issuance. Pursuant to the Subscription Agreement, the Company agreed to subscribe for an additional 750 convertible debenture units (the "2023 Subsequent Units") at a price of $ 750,000 subject to obtaining certain shareholder approvals. The Subsequent Units contain the same terms as the Initial Units, with each Subsequent Unit consisting of (i) $ 1,000 principal amount convertible promissory notes ("2023 Subsequent Notes") and (ii) 5,405 common share purchase warrants of IntelGenx ("2023 Subsequent Warrants"). Effective September 30, 2023, IntelGenx and the Company amended the Subscription Agreement (the “Amended Subscription Agreement”), allowing the Company, subject to obtaining certain shareholder approvals, the "Call Option" to purchase up to an additional 7,401 convertible debenture units (the “Call Option Units”). The Call Option Units contain the same terms as the Initial Units, with each Call Option Unit consisting of (i) $ 1,000 principal amount convertible promissory notes, and (ii) 5,405 common share purchase warrants of IntelGenx. The issuance of any Call Option Unit shall result in a corresponding reduction in the Company's remaining purchase right pursuant to the IntelGenx SPA executed in May 2021 (the “2021 Purchase Right”), with such right to be reduced by the maximum number of shares of common stock issuable in connection with such Call Option Units, and (ii) in the event that the 2021 Purchase Right has been fully or partially exercised such that the aggregate number of shares of common stock issued thereunder together with the number of shares of common stock issuable in accordance with the Call Option Units would exceed 100,000,000 , the number of shares of common stock that may be issued in connection with the Call Option Units shall be reduced such that the aggregate number of shares of common stock issued thereunder together with the number of shares of common stock issuable in accordance with the Call Option Units does not exceed 100,000,000 . The maximum number of shares of common stock available under the 2021 Purchase Right was reduced from 130,000,000 shares of common stock to 100,000,000 shares of common stock, such that in no event shall the aggregate number of shares of common stock issuable in accordance with the Call Option Units and the 2021 Purchase Right exceed 100,000,000 . There are limits over the conversion of the Initial Units, Subsequent Units, Call Options Units and the IntelGenx Term Loan (as defined below in Note 6) into common shares. The Company qualified for and elected to account for its investment in the convertible debenture units and call option under the fair value option. The Company believes that the fair value option better reflects the underlying economics of the convertible debenture units and call option. The convertible promissory notes are accounted for at fair value under ASC 320 and recorded in Short-term convertible notes receivable - related party in the unaudited condensed consolidated balance sheet, as described further in Note 6. The warrants and call option are accounted for pursuant to the fair value option election and recorded in Other investments held at fair value in the unaudited condensed consolidated balance sheet. For the 2023 Initial Units, the Company determined that the initial aggregate fair value of its $ 2.2 million investment was equal to the transaction price and recorded the 2023 Initial Notes at $ 1.5 million and the 2023 Initial Warrants at $ 0.7 million resulting in no initial gain or loss recognized in the consolidated statements of operations. The Company will recognize subsequent changes in fair value of the 2023 Initial Notes (see Note 6) and 2023 Initial Warrants as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the consolidated statements of operations. As of September 30, 2024 and December 31, 2023 , the fair value of the 2023 Initial Warrants was zero and $ 0.7 million, respectively. For the three and nine months ended September 30, 2024 , the Company recognized no change in fair value and a $ 0.7 million loss in Change in fair value of assets and liabilities, net relating to the 2023 Initial Warrants in its unaudited condensed consolidated statements of operations, respectively. There was an immaterial change in fair value relating to the 2023 Initial Warrants in the Company's unaudited condensed consolidated statements of operations for the three and nine months ended September 30, 2023, respectively. In November 2023, upon shareholder approval, the Company paid $ 750,000 for the 2023 Subsequent Units. The Company determined that the initial aggregate fair value of its $ 0.8 million investment was equal to the transaction price and recorded the 2023 Subsequent Notes at $ 0.6 million and the 2023 Subsequent Warrants at $ 0.2 million resulting in no initial gain or loss recognized in the consolidated statements of operations. The Company will recognize subsequent changes in fair value of the 2023 Subsequent Notes (see Note 6) and 2023 Subsequent Warrants as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the consolidated statements of operations. As of September 30, 2024 and December 31, 2023 , the fair value of the 2023 Subsequent Warrants was zero and $ 0.2 million, respectively. For the three and nine months ended September 30, 2024, the Company recognized no change in fair value and a $ 0.2 million loss in Change in fair value of assets and liabilities, net relating to the 2023 Subsequent Warrants in its unaudited condensed consolidated statements of operations, respectively. At December 31, 2023, the Call Option was recorded in Other investments held at fair value on the consolidated balance sheet with an estimated fair value of $ 5.1 million. The Call Option is additional value conveyed to the Company relating to its investment in and Strategic Development Agreement with IntelGenx. Accordingly, the Company also recorded a $ 5.1 million deferred credit, included in Other liabilities in the consolidated balance sheet. As appropriate, the Company will account for the deferred credit as a reduction of research and development expense in its consolidated statements of operation until the credit is exhausted or the Company is no longer receiving goods or services from IntelGenx. As of September 30, 2024 and December 31, 2023 , the fair value of the Call Option was zero and $ 5.2 million, respectively. For the three and nine months ended September 30, 2024, the Company recognized no change in fair value and a $ 5.2 million loss in Change in fair value of assets and liabilities, net relating to the Call Option in its unaudited condensed consolidated statements of operations, respectively. 2024 Term Loan Warrants In March 2024, the Company and IntelGenx entered into a third amendment to the amended and restated loan agreement (the "Third Amendment"), as further described in Note 6 below. In connection with the Third Amendment, the Company received warrants to purchase up to 4 million shares of IntelGenx Common Shares at an exercise price of $ 0.17 , subject to certain adjustments and beneficial ownership limitations ("2024 Warrants"). The Company recorded the 2024 Warrants fair value of $ 0.4 million in Other investments held at fair value in the consolidated balance sheet, with a corresponding deferred vendor credit included in Other liabilities in the consolidated balance sheet. As of September 30, 2024 , the 2024 Warrants have a fair value of zero . For the three and nine months ended September 30, 2024 , the Company recorded no change in fair value and a $ 0.4 million loss in Change in fair value of assets and liabilities, net for the change in fair value of the 2024 Warrants, respectively. Strategic Development Agreement Pursuant to the Strategic Development Agreement, the Company engages IntelGenx to conduct research and development projects (“Development Project”) using IntelGenx’s proprietary oral thin film technology. Under the terms of the Strategic Development Agreement, the Company can select four (4) program products. As of the effective date of the Strategic Development Agreement, the Company nominated two (2) program products - DMT and Salvinorin A. 20 % of any funds that IntelGenx received or will receive through the Company’s equity investment under the IntelGenx SPA will be available to be credited towards research and development services that IntelGenx conducts for the Company under the Development Projects. The Company is eligible to receive a total credit of $ 2.5 million. For the three and nine months ended September 30, 2024 , research and development expense relating to the Strategic Development Agreement were $ 0.2 million and $ 0.6 million, respectively, which was applied as a reduction in research and development expenses in accordance with the Strategic Development Agreement. For the three and nine months ended September 30, 2023 , research and development expense relating to the Strategic Development Agreement were $ 0.1 million and $ 0.3 million, respectively, which was applied as a reduction in research and development expenses in accordance with the Strategic Development Agreement. Other investments The Company has accounted for its Other investments that do not have a readily determinable fair value under either the alternative measurement under ASC 321 or as an equity method investment. Under the measurement alternative, the Company measured its Other investments at cost, less any impairment, plus or minus, if any, observable price changes in orderly transactions for an identical or similar investment of the same issuer. For equity method investments where the Company has not elected the fair value option, it records gains (losses) from investments in equity method investees, net of tax, for its proportionate share of the underlying company’s net results until the investment balance is adjusted to zero. If the Company makes subsequent additional investments in that same company, it may record additional gains (losses) based on changes to its investment basis and also may record additional income (loss) in equity method investments. The Company’s investments in the preferred stock of Innoplexus, GABA, defined below, and Beckley Psytech Limited are not considered as in-substance common stock due to the existence of substantial liquidation preferences and therefore did not have subordination characteristics that were substantially similar to the common stock. During the three and nine months ended September 30, 2024 and 2023, the Company evaluated all of its other investments to determine if certain events or changes in circumstance had a significant adverse effect on the fair value of any of its investments in non-consolidated entities. Based on this analysis, the Company did not note any impairment indicators associated with the Company’s Other investments. During the three and nine months ended September 30, 2024 and 2023 there were no observable changes in price recorded related to the Company’s Other investments. As of September 30, 2024 and December 31, 2023, the carrying values of Other investments, which consisted of investments in the investee’s preferred stock not in the scope of ASC 323 were as follows (in thousands): September 30, 2024 December 31, 2023 Beckley Psytech Limited $ 33,893 $ — GABA Therapeutics, Inc. — 1,838 Innoplexus AG — — Total $ 33,893 $ 1,838 Beckley Psytech Limited Beckley Psytech Limited ("Beckley Psytech") is a clinical stage biotechnology company dedicated to improving the lives of people suffering from neuropsychiatric disorders by transforming psychedelics into effective and rapid-acting clinical medicines. Its most advanced programs are focused on the development of psychedelic-based medicines to treat people with treatment resistant depression and major depressive disorder. Subscription and shareholders' agreement On January 3, 2024, the Company entered into a subscription and shareholders' agreement with Beckley Psytech and certain other shareholders as identified in the agreement (the "SSA"). Pursuant to the terms of the SSA, the Company (a) has the right to acquire 24,096,385 newly issued series C preferred shares, par value £ 0.0001 per share, of Beckley Psytech (the “Series C Shares”) for a total purchase price of $ 40 million (the “Primary Investment”); and (b) undertakes to enter into a Share Purchase Deed (the “Secondary Sale SPA”) within 10 business days, pursuant to which the Company will acquire a total of 11,153,246 shares of Beckley Psytech from certain existing shareholders of Beckley Psytech (the “Secondary Sale” and together with the Primary Investment, the “Investment”), all of which will be re-designated into Series C Shares immediately prior to completion of the Secondary Sale, for a total purchase price of $ 10 million. In connection with the SSA, the Company acquired, pursuant to an equity warrant instrument between the Company and Beckley Psytech, 24,096,385 warrants to purchase an amount of Series C shares equal to the lesser of (i) 24,096,385 Series C Shares; or (ii) such number of Series C Shares (rounded up to the nearest whole number) as immediately after their issuance would, together with all shares held by the Company in the issued share capital of Beckley Psytech, equal less than 50 % of Beckley Psytech’s fully diluted share capital, and each such warrant is exercisable at an exercise price of $ 2.158 per share ("Series C Warrants"). Also under the SSA, the Company will have the right to receive additional warrants to purchase Series C Shares in the event Beckley Psytech issues equity or equity linked securities pursuant to a deferred equity arrangement in connection with a prior acquisition made by Beckley Psytech, each such warrant is exercisable at an exercise price of $ 1.66 per share. Each of the warrants described above is exercisable upon delivery of a written notice to Beckley Psytech ("Additional Warrants"). Initial Subscription On January 3, 2024, the Company made an initial payment of $ 25 million for 15,060,241 Series C Shares at a subscription share price of $ 1.66 (“Initial Shares”) and delivered the executed deferred payment escrow agreement ("Escrow Agreement") to Beckley Psytech which was the condition for the closing or completion of the transaction (“Initial Subscription”). Secondary Sale On January 18, 2024, the Company and Beckley Psytech entered into the Secondary Sale SPA pursuant to which the Company agreed to purchase 11,153,246 , £ 0.0001 par value, re-designated Series C shares (the “Secondary Sale Shares”) at a price of $ 0.8966 from the existing shareholders for an aggregate consideration of $ 10 million. On January 18, 2024, the Secondary Sale Shares were acquired by the Company. The Company paid a total of $ 35.0 million upon closing of the Initial Subscription and Secondary Shares Sale. The Company determined that the Additional Warrants meet the definition of a derivative instrument under ASC 815 and recorded the $ 2.6 million fair value in Other investments held at fair value in the unaudited condensed consolidated balance sheet, with subsequent changes in fair value being reflected through the unaudited condensed consolidated statement of operations in the Change in fair value of assets and liabilities, net. The Company qualified for and elected to account for the remaining investment acquired per the SSA using the measurement alternative under ASC 321, and is included in Other Investments in the unaudited condensed consolidated balance sheet. The Company applied a calibrated model for the remaining $ 32.4 million investment, to account for the Initial Shares, option to purchase the Deferred Shares, Secondary Shares, and Series C Warrants, on a relative fair value basis resulting in no initial gain or loss recognized in the consolidated statements of operations. Deferred Shares On January 5, 2024, subject to the terms of the Escrow Agreement, the Company deposited $ 15.0 million into an escrow account. Prior to April 1, 2025, Beckley Psytech may, at its sole discretion, draw down up to $ 5.0 million from the escrow account, with the balance to be paid to Beckley Psytech at April 1, 2025. Beckley shall credit as fully-paid such corresponding number of Series C Shares as corresponds with the value of such draw-down. The total number of deferred payment shares ("Deferred Shares") is 9,036,144 with a share price of $ 1.66 . As of September 30, 2024 , Beckley Psytech has not made any draws against the escrow account. The Company reflects the $ 5.0 million Beckley Psytech may draw down at its sole discretion and the remaining $ 10.0 million held in escrow in Short-term restricted cash for other investments within the unaudited condensed consolidated balance sheets as of September 30, 2024. Additional Warrants In May 2024, Beckley Psytech issued equity pursuant to the deferred equity arrangement, and, per the SSA, the Company received 4,393,400 warrants. T he Company determined that once received the Additional Warrants will no longer meet the definition of a derivative instrument under ASC 815. The Company qualified for and elected to account for the warrants under ASC 321, and recorded the warrants received in Other Investments in the unaudited condensed consolidated balance sheet. At the time of receipt, the warrants had a fair value of $ 1.5 million. As of September 30, 2024, the Additional Warrants had a fair value of $ 1.7 million recorded in Other investments held at fair value in the unaudited condensed consolidated balance sheet. The Company recorded a $ 0.1 million loss and $ 0.6 million gain for the three and nine months ended September 30, 2024 within the Change in fair value of assets and liabilities, net in its unaudited condensed consolidated statements of operations, respectively. GABA Therapeutics, Inc. GABA Therapeutics, Inc. ("GABA") is a California based biotechnology company focused on developing GRX-917 for anxiety, depression and a broad range of neurological disorders. The Company is deemed to have significant influence over GABA through its total ownership interest in GABA’s equity, including the Company’s investment in GABA’s preferred stock, and the Company’s noncontrolling representation on GABA’s board of directors. Common Stock Investment The Company’s investment in GABA’s common stock was accounted for in accordance with the equity method. In November 2020 the Company exercised its option to purchase additional shares of common stock of GABA at a price of approximately $ 1.8 million pursuant to an Omnibus Amendment Agreement under which the Right of First Refusal and Co-Sale Agreement was amended. Pursuant to the amended Right of First Refusal and Co-Sale Agreement, the Company also has the option but not the obligation to purchase additional shares of common stock for up to $ 2.0 million from the existing common shareholders. The carrying value of the investment in GABA common stock was reduced to zero as of Dece mber 31, 2020 due to IPR&D charges with no alternative future use and remained zero as of September 30, 2024. The Company's ownership of GABA common stock was 7.2 % and 3.6 % as of September 30, 2024 and December 31, 2023, respectively. Preferred Stock Investment The Company’s investment in GABA’s preferred stock did not meet the criteria for in-substance common stock. As such, the investment in GABA’s preferred stock is accounted for under the measurement alternative under ASC 321. In August 2019, GABA and the Company entered into the Preferred Stock Purchase Agreement (the “GABA PSPA”), whereby GABA issued shares of its Series A preferred stock to the Company at a price of approximately $ 5.5 million. At closing, the Company had an overall ownership interest of over 20 % in GABA and a noncontrolling representation on the board. Pursuant to the GABA PSPA, the Company was obligated to purchase additional shares of Series A preferred stock for up to $ 10.0 million with the same price per share as its initial investment, upon the achievement of specified contingent clinical development milestones, which were purchased in April and May 2021. The completion of the Series A Preferred stock purchase in May 2021 was deemed to be a reconsideration event at which point GABA was no longer deemed a VIE as GABA now had sufficient equity at risk to finance its activities through the initial development period without additional subordinated financial support. Entities that do not qualify as a VIE are assessed for consolidation under the voting interest model (“VOE model”). Under the VOE model, the Company consolidates the entity if it determines that it, directly or indirectly, has greater than 50 % of the voting shares and that other equity holders do not have substantive voting, participating or liquidation rights. While the Company holds greater than 50% of the outstanding equity interest of GABA, the Company does not have the power to control the entity. Concurrent with the exercise of the option, the Company executed a side letter with the other equity holders of GABA agreeing to forego the rights to additional seats on the board of directors, resulting in the Company lacking the ability to control the investee. The Company concluded that it does not have a controlling financial interest that would require consolidation under the VOE model and accounted for the investments in GABA preferred stock under the measurement alternative per ASC 321. In May 2021, GABA and the Company entered into an Amendment to Preferred Stock Purchase Agreement (the "Amended GABA PSPA”) under which the GABA PSPA was amended and shares of its Series A preferred stock were issued to the Company at a price of approximately $ 0.6 million. Pursuant to the Amended GABA PSPA, the Company is obligated to purchase additional shares of Series A preferred stock from GABA for up to $ 1.5 million with the same price per share as its initial investment upon the achievement of specified contingent clinical development milestones. In September 2022, pursuant to the Amended PSPA, GABA issued additional shares of its Series A preferred stock to the Company at a price of approximately $ 0.6 million based on the achievement of certain development milest ones. As of September 30, 2024 the Company's remaining obligation to purchase additional shares of Series A preferred stock from GABA is for up to $ 0.9 million at the same price per share as its initial investment upon the achievement of specified contingent milestones. In accordance with the Amended GABA PSPA, the Company also has the option but not the obligation to purchase the aforementioned additional shares of Series A preferred stock at any time prior to the achievement of any milestone at the same price per share as its initial investment. As of September 30, 2024 and December 31, 2023, the investment in GABA’s preferred stock was recorded in Other Investments on the unaudited condensed consolidated balance sheets. GABA’s net losses attributable to the Company were determined based on the Company’s ownership percentage of preferred stock in GABA and recorded to the Company’s investments in GABA preferred stock. During the three months ended September 30, 2024 and 2023 , the Company recognized its proportionate share of GABA’s net loss of an immaterial amount and $ 0.2 million, respectively, as losses from investments in equity method investees, net of tax on the unaudited condensed consolidated statements of operations. During the nine months ended September 30, 2024 and 2023, the Company recognized its proportionate share of GABA’s net loss of $ 2.0 million and $ 3.2 million, respectively, as losses from investments in

Notes Receivable

Notes Receivable	9 Months Ended
	Sep. 30, 2024
Receivables [Abstract]
Notes Receivable	6. Notes Receivable IntelGenx Technologies Corp. As of September 30, 2024, considering relevant facts and circumstances, the Company has estimated the fair value of the various notes receivables with IntelGenx to be based on the fair value of the underlying collateral of the secured debt and the relative seniority of the debt. As the DIP Loan (as defined below) is the senior secured debt, the Company will apply the fair value of the underlying collateral first to the DIP loan with the residual fair value in excess of the DIP Loan (as defined below) principal and interest being applied to the IntelGenx Term Loan. The Initial Order is an event of default under the terms of the various notes receivables, and, accordingly, the notes receivables have all been reflected as short-term as of September 30, 2024. IntelGenx Term Loan, as amended In March 2021, the Company and IntelGenx entered into a loan agreement (the “Original Loan Agreement” ) under which the Company provided a loan to IntelGenx for an aggregate principal amount of $ 2.0 million. In May 2021, the Company paid an additional advance of $ 0.5 million as an additional term loan. In September 2021, the Company entered into an amended and restated loan agreement which, among other things, increased the principal amount of loans available to IntelGenx by $ 6.0 million, for a total of up to $ 8.5 million, collectively the “Initial Tranches” . The additional $ 6.0 million loan amount was funded via two separate $ 3.0 million tranches in January 2022 and January 2023. The loan bears an annualized interest rate of 8 % and such interest is accrued daily. On January 1, 2023, the Company adopted ASU 2016-13, Financial Instruments – Credit Losses, as further discussed in Note 2, which resulted in a $ 0.4 million increase to accumulated deficit and allowance for credit losses related to the IntelGenx loan. In August 2023, the Company and IntelGenx entered into the first amendment to the amended and restated loan agreement (the “First Amendment” ) which, among other things, extended the maturity date from January 5, 2024 to January 5, 2025 and granted the Company additional security over any non-licensed intellectual property owned or controlled by IntelGenx. Effective September 2023, the Company and IntelGenx entered into a second amendment to the amended and restated loan agreement (the “Second Amendment”) which, subject to obtaining certain shareholder approvals, entitles the Company to convert any portion of the outstanding and unpaid principal and accrued interest into common shares of IntelGenx at a conversion price per share of $ 0.185 (the “Conversion Feature”). There are limits over the conversion of the IntelGenx Term Loan (as defined below), along with Initial Units, Subsequent Units, and Call Options Units into common shares. In November 2023, upon shareholder approval, the Conversion Feature was effective. The Company evaluated this modification subject to accounting guidance in ASU 2022-02, Financial Instruments – Credit Losses and determined the Conversion Feature was considered the addition of a substantive conversion option and the modification is more than minor. Therefore, the Second Amendment was treated as an extinguishment of the existing loan and the issuance of a new convertible debt instrument. The IntelGenx Term Loan, as amended, meets the definition of a security and was accounted for under ASC 320. Pursuant to the remeasurement event, the Company was eligible and has elected the fair value option to account for its investment in the IntelGenx Term Loan. The Company believes that the fair value option better reflects the underlying economics of the loan. The Company recorded the new convertible debt instrument at its fair value of $ 9.2 million in Convertible notes receivable – related party on the consolidated balance sheets. The IntelGenx Term Loan will be subsequently remeasured at each reporting date until settled or converted. The Company will recognize subsequent changes in fair value, including interest earned of the IntelGenx Term Loan in Change in fair value of assets and liabilities, net, a component of other income (expense), net in its consolidated statements of operations. In March 2024, the Company and IntelGenx entered into the Third Amendment (together with the Original Loan Agreement, the First Amendment, and the Second Amendment, the “IntelGenx Term Loan” ) pursuant to which the Company immediately provided an additional $ 1.0 million term loan ( “Tranche 1 Additional Term Loan” ), and would provide an additional $ 1.0 million term loan ( “Tranche 2 Additional Term Loan”) contingent upon certain of the Company's clinical milestones. The IntelGenx Term Loan, as amended includes a conversion feature that allows for: a) any portion of the outstanding and unpaid principal under the Initial Tranches and/or the Tranche 1 Additional Term Loan into conversion shares (the “Conversion Shares”) at a conversion price per share of $ 0.185 (the “Initial Conversion Price”); b) any accrued interest under the Initial Tranches into Conversion Shares at the Initial Conversion Price; c) any portion of the outstanding and unpaid principal under the Tranche 2 Additional Term Loan into Conversion Shares at a conversion price per share equal to the greater of: (1) the Initial Conversion Price; and (2) the 5-day volume-weighted average price (the “5-day VWAP”) of the Shares, less the maximum permitted discount under the applicable rules of the Stock Exchange, ending on the date immediately prior to the advancement of the Tranche 2 Additional Term Loan (the “Tranche 2 Conversion Price”); and d) any accrued interest under the Tranche 1 Additional Term Loan into Conversion Shares at the 5-day VWAP of the shares, less the maximum permitted discount under the applicable rules of the Stock Exchange, ending on the day that is the second business day before the day the Interest become due and payable (the “Interest Conversion Price” and, together with the Initial Conversion Price and the Tranche 2 Conversion Price, the “Conversion Price”), subject to Stock Exchange approval. In connection with the Third Amendment, the Company received warrants to purchase up to 4 million shares of IntelGenx Common Shares at an exercise price of $ 0.17 , subject to certain adjustments and beneficial ownership limitations, which were recorded at fair value of $ 0.4 million in Other investments held at fair value in the consolidated balance sheet, with a corresponding deferred vendor credit included in Other liabilities in the consolidated balance sheet. See Note 5 above for further discussion. As a result of the Third Amendment, the Company recorded the Tranche 1 Additional Term Loan principal of $ 1.0 million in Convertible notes receivable – related party on the consolidated balance sheet. In May 2024, the Company paid the Tranche 2 Additional Term Loan and recorded the principal of $ 1.0 million in Convertible notes receivable – related party on the consolidated balance sheet. As of September 30, 2024, the Company estimated that the fair value of the underlying collateral of the secured debt is less than the principal and interest of the DIP Loan (as defined below). Accordingly, the Company determined that the fair value of the IntelGenx Term Loan is zero as of September 30, 2024. As of December 31, 2023 , the $ 8.6 million fair value of the amended IntelGenx Term Loan was recorded in Convertible notes receivable – related party on the consolidated balance sheet. For the three months ended September 30, 2024, the Company recorded $ 7.0 million in Change in fair value of assets and liabilities, net for the change in fair value of IntelGenx Term Loan. For the nine months ended September 30, 2024, the Company recorded $ 11.1 million in Change in fair value of assets and liabilities, net for the change in fair value of IntelGenx Term Loan. For the three months ended September 30, 2024 and 2023 , the Company recognized zero and $ 0.2 million of interest income, respectively, associated with the IntelGenx Term Loan. For the nine months ended September 30, 2024 and 2023 , the Company recognized zero and $ 0.5 million of interest income, respectively, associated with the IntelGenx Term Loan. IntelGenx Convertible Notes On August 30, 2023, the Company and IntelGenx entered into the Subscription Agreement (as defined in Note 5), under which the Company paid IntelGenx $ 2.2 million for 2,220 convertible debenture units (the "Initial Units"), with each convertible debenture unit consisting of: (i) $ 1,000 principal amount convertible promissory notes (the “2023 Initial Notes”) bearing interest at a rate of 12.0 % per annum, payable quarterly in arrears beginning September 30, 2023, with all principal and accrued interest convertible into common shares of IntelGenx, at any time from the date that is six months following their issuance up to and including August 31, 2026 at a conversion price equal to $ 0.185 per common share; and (ii) 5,405 common share purchase warrants of IntelGenx, each exercisable at an exercise price of $ 0.26 per common share for a period of three years following their issuance. Pursuant to the Subscription Agreement, the Company agreed to subscribe for an additional 750 convertible debenture units (the "2023 Subsequent Units") at a price of $ 750,000 subject to obtaining certain shareholder approvals. The Subsequent Units contain the same terms as the Initial Units, with each Subsequent Unit consisting of (i) $ 1,000 principal amount convertible promissory notes ("2023 Subsequent Notes") and (ii) 5,405 common share purchase warrants of IntelGenx ("2023 Subsequent Warrants"). The Company qualified for and elected to account for its investment in the convertible debenture units and call option under the fair value option. The Company believes that the fair value option better reflects the underlying economics of the convertible debenture units and call option. The convertible promissory notes related to the debenture units are accounted for at fair value under ASC 320 and recorded in Short-term convertible notes receivable - related party in the unaudited condensed consolidated balance sheet. The Company will recognize unpaid interest and subsequent changes in fair value of the convertible promissory notes related to the debenture units as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the unaudited condensed consolidated statements of operations. The Company determined that the initial aggregate fair value of its $ 2.2 million investment was equal to the transaction price and recorded the 2023 Initial Notes at $ 1.5 million and the 2023 Initial Warrants at $ 0.7 million resulting in no initial gain or loss recognized in the consolidated statements of operations. In November 2023, upon shareholder approval, the Company paid $ 750,000 for the subscription of the 2023 Subsequent Units. The Company determined that the initial aggregate fair value of its $ 0.8 million investment was equal to the transaction price and recorded the 2023 Subsequent Notes at $ 0.6 million and the 2023 Subsequent Warrants at $ 0.2 million resulting in no initial gain or loss recognized in the unaudited condensed consolidated statements of operations. As of September 30, 2024, the Company has estimated the fair value of various notes receivables with IntelGenx based on the fair value of the underlying collateral of the secured debt. As the 2023 Initial Notes and 2023 Subsequent Notes are not secured by underlying collateral, the Company has determined the fair value of the 2023 Initial Notes and 2023 Subsequent Notes are zero, respectively, as of September 30, 2024. As of December 31, 2023 , the fair value of the 2023 Initial Notes and 2023 Subsequent Notes were $ 1.8 million and $ 0.5 million, respectively, and recorded in Convertible notes receivable – related party in the unaudited condensed consolidated balance sheets. For the three months ended September 30, 2024 , the Company recognized $ 0.9 million and $ 0.3 million in Change in fair value of assets and liabilities, net relating to the 2023 Initial Notes and 2023 Subsequent Notes, respectively, in its unaudited condensed consolidated statements of operations. For the nine months ended September 30, 2024, the Company recognized $ 1.8 million and $ 0.5 million in Change in fair value of assets and liabilities, net relating to the 2023 Initial Notes and 2023 Subsequent Notes, respectively in its unaudited condensed consolidated statements of operations. For the three and nine months ended September 30, 2023 , the company recognized $ 0.1 million and $ 0.1 million in Change in fair value of assets and liabilities, net relating to the 2023 Initial Notes, respectively, in its unaudited condensed consolidated statements of operations. Debtor-in-Possession Loan In May 2024, pursuant to the Initial Order authorizing the DIP Financing, the Company and IntelGenx entered into a senior secured super-priority, interim, non-revolving multiple draw credit facility ("DIP Loan") up to a maximum of CDN 8.0 million (USD $ 5.9 million). The DIP Loan bears an annualized interest rate equal to the National Bank of Canada prime rate, which was 6.45 % at September 30, 2024. The outstanding principal and interest of the DIP Loan is due and payable on the earlier of (i) September 30, 2024, (ii) the termination of the stay period in the CCAA proceedings, (iii) the CCAA proceedings are converted into a bankruptcy or receivership, (iv) implementation of a restructuring plan or sale of the IntelGenx business during the CCAA proceedings, or (v) an event of default as defined in the DIP Loan agreement. The Company qualified for and elected to account for the DIP Loan under the fair value option. The Company believes that the fair value option better reflects the underlying economics of the DIP Loan. The DIP Loan is accounted for at fair value under ASC 825 and recorded in Short term notes receivable - related party, net in the unaudited condensed consolidated balance sheet. The Company will recognize unpaid interest and subsequent changes in fair value of the DIP Loan Note as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the unaudited condensed consolidated statements of operations. As of September 30, 2024 , IntelGenx has drawn CDN $ 7.8 million (USD $ 5.7 million) pursuant to the DIP Loan. As of September 30, 2024, the fair value of the DIP Loan was $ 5.7 million and recorded in Short-term notes receivable - related party, net in the unaudited condensed consolidated balance sheets. For the three and nine months ended September 30, 2024, the Company recognized $ 0.2 million gain and an immaterial loss in Change in fair value of assets and liabilities, net, respectively, relating to the DIP Loan in its unaudited condensed consolidated statements of operations. The Company is committed to fund IntelGenx up to an additional CDN $ 0.2 million (USD $ 0.1 million ) as of September 30, 2024. Accordingly, the Company recorded a liability for the remaining balance of the DIP Loan ("Subsequent DIP Loan Commitment"). The Company qualified for and elected to account for the Subsequent DIP Loan Commitment under the fair value option. The Company believes that the fair value option better reflects the underlying economics of the Subsequent DIP Loan Commitment. The Subsequent DIP Loan Commitment is accounted for at fair value under ASC 825 and recorded at fair value and is recorded in Other current liability in the unaudited condensed consolidated balance sheet. The Company will recognize changes in fair value of the contingent forward as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the unaudited condensed consolidated statements of operations. As of September 30, 2024 , the fair value of the Subsequent DIP Loan Commitment was $ 0.1 million and recorded in Other current liability in the unaudited condensed consolidated balance sheet. For the three and nine months ended September 30, 2024 , the Company recognized a $ 0.5 million gain and a $ 0.5 million gain, respectively. IntelGenx 2023 Term Loan Note In December 2023, the Company and IntelGenx entered into a new term loan agreement under which the Company provided the aggregate principal amount of $ 500,000 (the “2023 Term Loan Note”). The loan bears an annualized interest rate of 14.0 % compounding monthly. Principal and interest outstanding shall be due and payable from proceeds of future IntelGenx fundraising. The outstanding principal and interest on the 2023 Term Loan Note is due and payable under the terms of the agreement. The Company qualified for and elected to account for the 2023 Term Loan Note under the fair value option. The Company believes that the fair value option better reflects the underlying economics of the 2023 Term Loan Note. The IntelGenx 2023 Term Loan Note is accounted for at fair value under ASC 825 and recorded in Short-term notes receivable - related party, net in the consolidated balance sheet. The Company will recognize unpaid interest and subsequent changes in fair value of the IntelGenx 2023 Term Loan Note as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the consolidated statements of operations. As of September 30, 2024 , the Company has estimated the fair value of various notes receivables with IntelGenx based on the fair value of the underlying collateral of the secured debt. As the 2023 Term Loan Note is not secured by underlying collateral, the Company has determined the fair value of the 2023 Term Loan Note is zero as of September 30, 2024. As of December 31, 2023 , the 2023 Term Loan Note had a fair value of $ 0.5 million and recorded in Short-term notes receivable - related party, net. For the three and nine months ended September 30, 2024, the Company recognized a $ 0.2 million loss and $ 0.5 million loss, respectively in Change in fair value of assets and liabilities, net relating to the IntelGenx 2023 Term Loan Note in its unaudited condensed consolidated statements of operations.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurement	7. Fair Value Measurement The following table presents information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis and indicates the fair value hierarchy of the valuation (in thousands): Fair Value Measurements as of September 30, 2024 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 829 $ — $ — $ 829 Investment in securities at fair value: U.S. treasuries — 51,358 — 51,358 U.S. government agencies — 4,599 — 4,599 Other investments held at fair value 43,506 — 1,721 45,227 Short-term notes receivable - related party, net — — 5,700 5,700 $ 44,335 $ 55,957 $ 7,421 $ 107,713 Liabilities: Other current liability $ — $ — $ 147 $ 147 Contingent consideration liability - related parties — — 650 650 Contingent consideration liability — — 1,388 1,388 2018 convertible promissory note conversion option - related party — — 758 758 2018 convertible promissory note conversion option — — 1,239 1,239 $ — $ — $ 2,796 $ 2,796 Fair Value Measurements as of December 31, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 56 $ — $ — $ 56 Investment in securities at fair value: U.S. treasuries — 67,119 — 67,119 Corporate notes/bonds — 5,007 — 5,007 U.S. government agencies — 37,097 — 37,097 Other investments held at fair value 83,701 — 6,124 89,825 Convertible notes receivable - related party — — 11,202 11,202 $ 83,757 $ 109,223 $ 17,326 $ 210,306 Liabilities: Contingent consideration liability - related parties $ — $ — $ 620 $ 620 Contingent consideration liability — — 1,637 1,637 2018 convertible promissory note conversion option — — 2,385 2,385 $ — $ — $ 4,643 $ 4,643 Investment in securities at fair value The Company elected the fair value option for the securities in the investment portfolio. The fair value is based on quoted market prices, when available. When a quoted market price is not readily available, the Company uses the market price from its last sale of similar assets. The cash and cash equivalents held by the Company are categorized as Level 1 investments as quoted market prices are readily available for these investments. All other investments in the investment portfolio are categorized as Level 2 investments as inputs utilized to fair value these securities are either directly or indirectly observable, such as the market price from the last sale of similar assets. The Company purchases investment grade short-term debt securities which are rated by nationally recognized statistical credit rating organizations in accordance with its investment policy. This policy is designed to minimize the Company's exposure to credit losses and to ensure that adequate liquidity is maintained at all times to meet anticipated cash flow needs. The unrealized gains and losses on the available-for-sale securities, represented by change in the fair value of the investment portfolio, is reported in other income (expense), net in the unaudited condensed consolidated statements of operations. Since the investment in the available-for-sale securities are already measured at fair value, no separate credit losses would be recorded in the unaudited condensed consolidated financial statements. For three months ended September 30, 2024 and 2023, the Company recognized a $ 0.9 million and $ 1.8 million gain, respectively, related to the change in fair value in its available for sale securities recorded as a Change in fair value of assets and liabilities, net in its unaudited condensed consolidated statements of operations. For nine months ended September 30, 2024 and 2023 , the Company recognized a $ 3.2 million and $ 3.3 million gain, respectively, related to the change in fair value in its available for sale securities recorded as a Change in fair value of assets and liabilities, net in its unaudited condensed consolidated statements of operations. Other investments held at fair value COMPASS Pathways plc As described in Note 5 above, pursuant to the August 2023 financing, the Company determined that it no longer had significant influence and accounted for its COMPASS investment at fair value under ASC 321 with any changes in fair value recorded as a Change in fair value of assets and liabilities, net in its unaudited condensed consolidated statements of operations. The Company determines the fair value of its COMPASS investment by taking the publicly available share price as of the balance sheet date multiplied by the number of shares the Company holds. There are no non-observable inputs in determining the fair value. For the three and nine months ended September 30, 2024, the Company recorded $ 3.9 million and $ 22.0 million of Change in fair value of assets and liabilities, net, respectively. For the three and nine months ended September 30, 2023 , the Company recorded $ 69.0 million and $ 69.0 million of Change in fair value of assets and liabilities, net, respectively. IntelGenx As described in Note 5, the Company's investment in IntelGenx includes common shares, 2023 Initial Warrants, 2023 Subsequent Warrants, and 2024 Warrants, (the 2023 Initial Warrants, 2023 Subsequent Warrants, and 2024 Warrants are collectively referred to as the “Warrants”), and Call Option. The Company determined that the Warrants and the Call Option do not meet the definition of a derivative instrument under ASC 815. The Company has classified the common shares as Level 2 assets and the Warrants and the Call Option as Level 3 assets in the fair value hierarchy. The Warrants and Call Option are measured at fair value on a quarterly basis and any changes in the fair value will be recorded as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the consolidated statements of operations. As of September 30, 2024, considering relevant facts and circumstances, the Company has estimated zero fair value for the Warrants and the Call Option (Note 5). The fair value of IntelGenx Common Shares, which is included in Other investments held at fair value in the consolidated balance sheet, was also zero as of September 30, 2024 and December 31, 2023 (Note 5). As of December 31, 2023, the Warrants and Call Option were recorded at fair value utilizing the Black-Scholes option pricing model. The Black Scholes option pricing model is based on the estimated market value of the underlying IntelGenx Common Shares at the valuation measurement date, the remaining contractual term of the Warrants and Call Option, risk-free interest rates, expected dividends, and expected volatility of the price of the underlying IntelGenx Common Shares. The expected volatility is based on a peer group volatility which is a Level 3 input within the fair value hierarchy. As of September 30, 2024, the fair value of the 2023 Initial Warrants, 2023 Subsequent Warrants, 2024 Warrants and Call Option were all zero (Note 5). As of December 31, 2023 , the fair value of the 2023 Initial Warrants, the 2023 Subsequent Warrants and Call Option was $ 0.7 million, $ 0.2 million and $ 5.2 million, respectively, and recorded in Other investments held at fair value in the unaudited condensed consolidated balance sheets. The significant unobservable inputs that are included in the valuation of the Warrants and Call Option as of December 31, 2023 are (i) estimated market value of the underlying IntelGenx Common Shares of $ 0.13 , including discount for lack of marketability of 5 % and (ii) volatility of 100 % for the period. An additional significant unobservable input that is included in the valuation of the Call Option as of December 31, 2023 is discount rate of 45.9 % based on an assessment of IntelGenx credit risk and market yields of companies with similar credit risk. IntelGenx notes receivable As described in Note 6, the Company's notes receivable with IntelGenx include the IntelGenx Term Loan, the 2023 Initial Notes, the 2023 Subsequent Notes, the DIP Loan, and the 2023 Term Loan Note. As of September 30, 2024 , considering relevant facts and circumstances, the Company has estimated the fair value of the various notes receivables with IntelGenx based on the fair value of the underlying collateral of the secured debt and the relative seniority of the debt. As the DIP loan is the senior secured debt, the Company will apply the fair value of the underlying collateral first to the DIP loan with the residual fair value in excess of the DIP Loan principal and interest being applied to the IntelGenx Term Loan. The Company has estimated the fair value of the underlying collateral, which includes the fair value of the intangible assets which was determined based on probability adjusted forecasted revenue and expenses and a discount rate of 12.5 %. As of September 30, 2024, the fair value of the DIP Loan was $ 5.7 million and recorded in Short-term notes receivable - related party, net in the unaudited condensed consolidated balance sheets. As the 2023 Initial Notes, 2023 Subsequent Notes, and the 2023 Term Loan Note (collectively the "IntelGenx Unsecured Debt") are not secured by the underlying collateral, the Company has determined the fair value of IntelGenx Unsecured Debt to be zero as of September 30, 2024. IntelGenx subsequent DIP loan commitment As described in Note 6, the Company is committed to fund up to an additional CDN $ 0.2 million (USD $ 0.1 million) pursuant to the DIP Loan. For the Subsequent DIP Loan Commitment, the Company estimated the fair value based on the present value of the estimated net fair value of the Subsequent DIP Loan Commitment based on expected future payments pursuant to the DIP Loan. Beckley Psytech Under the Beckley Psytech SSA, the Company will have the right to receive Additional Warrants to purchase Series C Shares in the event Beckley Psytech issues equity or equity linked securities pursuant to a deferred equity arrangement in connection with a prior acquisition made by Beckley Psytech. The Company determined that the Additional Warrants meet the definition of a derivative instrument under ASC 815 and recorded the Additional Warrants at fair value with subsequent changes in fair value being reflected through the condensed consolidated statement of operations in the Change in fair value of assets and liabilities, net. The Additional Warrants have a fair value of $ 1.7 million as of September 30, 2024. The significant unobservable inputs that are included in the valuation of the Additional Warrants as of September 30, 2024 are (i) probability of issuances under the deferred equity arrangement of 50 %- 80 %, and (ii) volatility of 90 %. Contingent consideration liability – related parties The contingent consideration liability—related parties in the table above relates to milestone and royalty payments in connection with the 2018 acquisition of Perception Neuroscience Holdings, Inc. (“Perception”) and InnarisBio, Inc. ("InnarisBio"). The fair value of the contingent consideration liability—related parties was determined based on significant inputs not observable in the market, which represent Level 3 measurements within the fair value hierarchy. The fair value of the contingent milestone and royalty liabilities was estimated based on the discounted cash flow valuation technique. The technique considered the following unobservable inputs: • the probability and timing of achieving the specified milestones and royalties as of each valuation date, • the probability of executing the license agreement, • the expected first year of revenue, and • market-based discount rates. Perception The fair value of the Perception contingent milestone and royalty liabilities could change in future periods depending on prospects for the outcome of R-Ketamine milestone meetings with the FDA or other regulatory authorities, and whether the Company realizes a significant increase or decrease in sales upon commercialization. The most significant assumptions in the discounted cash flow valuation technique that impacts the fair value of the milestone contingent consideration are the projected milestone timing and the probability of the milestone being met. Further, significant assumptions in the discounted cash flow that impacts the fair value of the royalty contingent consideration are the projected revenue over ten years, the timing of royalties on commercial revenue, and the probability of success rate for a commercial R-Ketamine product. The valuations as of September 30, 2024 and December 31, 2023, respectively, used inputs that were unobservable inputs with the most significant being the discount rates for royalties on projected commercial revenue and clinical milestones and probability of success estimates over the following ten years, which represent Level 3 measurements within the fair value hierarchy. The fair value of the contingent milestone and royalty liabilities for Perception was estimated to be $ 0.7 million and $ 0.6 million as of September 30, 2024 and December 31, 2023, respectively. The fair value of the Perception contingent consideration liability – related parties was calculated using the following significant unobservable inputs: September 30, 2024 December 31, 2023 Valuation Technique Significant Unobservable Inputs Input Range Input Range Discounted cash flow Milestone contingent consideration: Discount rate 11.3 % 13.5 % Probability of the milestone 28.0 % 28.0 % Discounted cash flow with Scenario-Based Method Royalty contingent consideration: Discount rate for royalties 11.0 %- 12.7 % 13.0 % - 14.2 % Discount rate for royalties on milestones 11.0 %- 12.7 % 13.0 % - 14.2 % Probability of success rate 28.0 % 13.4 % - 28.0 % InnarisBio The fair value of the contingent milestone and royalty liabilities for InnarisBio was immaterial as of September 30, 2024 and December 31, 2023, respectively. Contingent Consideration Liability The contingent consideration liability in the table above relates to milestone payments in connection with the acquisition of DemeRx IB and TryptageniX. The fair value of the contingent consideration liability was determined based on significant inputs not observable in the market, which represent Level 3 measurements within the fair value hierarchy. The fair value of the contingent milestone and royalty liabilities was estimated based on the discounted cash flow valuation technique. The technique considered the following unobservable inputs: • market-based discount rates, and • the probability and timing of achieving the specified milestones as of each valuation date. DemeRx In October 2023, the Company and DemeRx, Inc. entered into a Stock Purchase and Framework Agreement which resulted in the Company's acquisition of DemeRx, Inc.’s equity ownership of DemeRx IB (the “Stock Purchase”), in exchange for consideration that included, among other items, earn-out consideration of up to an additional $ 8.0 million payable to DemeRx, Inc. ("DemeRx") contingent upon the achievement of certain development milestones directly related to DemeRx IB’s oral capsule formulation of ibogaine (“DMX-1002”) program. The earn-out consideration was recorded at fair value in contingent consideration as a liability under ASC 480 and the fair value is adjusted each quarter and reflected in other income and expense in the statement of operations. The fair value of the DemeRx contingent milestone could change in future periods depending on prospects for the outcome of ibogaine milestone meetings with the FDA or other regulatory authorities. The most significant assumptions in the discounted cash flow valuation technique that impacts the fair value of the milestone contingent consideration are the projected milestone timing and the probability of the milestone being met. The valuations as of September 30, 2024 and December 31, 2023 used inputs that were unobservable inputs with the most significant being the discount rates and the probability of success of certain clinical milestones, which represent Level 3 measurements within the fair value hierarchy. The fair value of the contingent milestone for DemeRx was estimated to be $ 1.2 and $ 1.4 million as of September 30, 2024 and December 31, 2023. The fair value of the DemeRx contingent consideration liability – related parties was calculated using the following significant unobservable inputs: September 30, 2024 December 31, 2023 Valuation Technique Significant Unobservable Inputs Input Range Input Range Discounted cash flow Milestone contingent consideration: Discount rate 11.3 %- 11.4 % 13.9 % Probability of the milestone 20.0 % - 25.0 % 20.0 % - 25.0 % TryptageniX The fair value of the contingent liability for TryptageniX was estimated to be $ 0.2 million and $ 0.2 million as of September 30, 2024, and December 31, 2023, respectively. The contingent liability is comprised of R&D milestone success fee payments and royalties payments. The fair value of the success fee liability was estimated based on the scenario-based method within the income approach. The fair value of the success fee liability for TryptageniX was determined based on significant unobservable inputs, including the discount rate, estimated probabilities of success, and timing of achieving certain clinical milestones. The fair value of the royalties liability was determined to be de minimis as the products are in the early stages of development. The Company will continue to assess the appropriateness of the fair value of the contingent liability as the products continue through development. Convertible Promissory Note As described in Note 11, in December 2023 and April 2024, the Company entered into subscription agreements with each of a noteholder and a related party noteholder, respectively (together the "Subscription Agreement") whereby each of the noteholder and the related party noteholder exchanged their ATAI Life Sciences AG notes (the "Old AG Notes") into the same principal amount of new convertible notes issued by ATAI Life Sciences N.V. (the "New NV Notes"). The exchange resulted in the New NV Notes conversion option no longer meeting the equity classification criteria. Accordingly, at the time of the exchange modification, the Company bifurcated the conversion option and reclassified the conversion option fair value from equity to a liability and is included in Short-term convertible promissory notes and derivative liability and Short-term convertible promissory notes and derivative liability - related party, respectively, in the unaudited condensed consolidated balance sheets. The conversion option is measured at fair value on a quarterly basis and any changes in the fair value will be recorded as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the unaudited condensed consolidated statements of operations. For the three and nine months ended September 30, 2024, the Company recognized a loss of $ 1.0 million and $ 3.9 million, respectively, as a result of the change in fair value of the New NV Notes. The conversion option fair value was estimated utilizing the Black-Scholes option pricing model. The Black Scholes option pricing model is based on the estimated market value of the underlying common stock at the valuation measurement date, the remaining contractual term of the Conversion Feature, risk-free interest rates, expected dividends, and expected volatility of the price of the underlying common stock. The expected volatility is based upon the historical volatility of daily lognormal returns on atai shares, which is a Level 3 input within the fair value hierarchy. The significant unobservable input that is included in the valuation of the Conversion Feature as of September 30, 2024 and December 31, 2023 is volatility of 75.0 % and 78.6 %, respectively. The following table provides a roll forward of the aggregate fair values of the Company’s financial instruments described above, for which fair value is determined using Level 3 inputs (in thousands): IntelGenx Debt (1) IntelGenx Investments Held at Fair Value (2) IntelGenx Subsequent DIP Loan Commitment Contingent (3) Contingent (4) New NV Notes Conversion Feature Beckley Psytech Additional Warrants Balance as of December 31, 2023 $ 11,202 $ 6,124 $ — $ 620 $ 1,637 $ 2,385 $ — Initial fair value of instrument 988 420 — — — — 2,645 Change in fair value, including interest 1,712 1,429 — ( 13 ) ( 231 ) 1,734 — Balance as of March 31, 2024 $ 13,902 $ 7,973 $ — $ 607 $ 1,406 $ 4,119 $ 2,645 Initial fair value of instrument 3,425 — 680 — — 3,590 — Change in fair value, including interest ( 7,455 ) ( 7,973 ) — ( 27 ) ( 32 ) ( 4,780 ) 720 Balance as of June 30, 2024 $ 9,872 $ — $ 680 $ 580 $ 1,373 $ 2,929 $ 3,364 Initial fair value of instrument $ 3,830 — — — — — — Additional Warrants received $ — — — — — — ( 1,538 ) Change in fair value, including interest $ ( 8,002 ) — ( 533 ) 70 15 ( 932 ) ( 105 ) Balance as of September 30, 2024 $ 5,700 $ — $ 147 $ 650 $ 1,388 $ 1,997 $ 1,721 Convertible notes receivable - related party IntelGenx 2023 Initial Warrants Contingent Balance as of December 31, 2022 $ — $ — $ 953 Initial fair value of instrument — — — Change in fair value — — ( 35 ) Extinguishment of liability — — — Balance as of March 31, 2023 $ — $ — $ 918 Initial fair value of instrument — Change in fair value — — ( 76 ) Extinguishment of liability — — — Balance as of June 30, 2023 $ — $ — $ 842 Initial fair value of instrument 1,497 724 — Change in fair value, including interest 22 — 58 Extinguishment of liability — — — Balance as of September 30, 2023 $ 1,519 $ 724 $ 900 (1) Includes the IntelGenx Term Loan, the 2023 Initial Notes, the 2023 Subsequent Notes, the DIP Loan, and the 2023 Term Loan Note. (2) Includes the 2023 Initial Warrants, the 2023 Subsequent Warrants, the 2024 Warrants, and the Call Option Units. (3) Includes Perception milestone based contingent consideration liability. (4) Includes contingent consideration liability related to DemeRx IB Stock Purchase and contingent consideration liability related to the TryptageniX research and development milestone success fee payments and royalties payments.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2024
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expenses and other current assets	8. Prepaid Expenses and Other Current Assets Prepaid expenses consist of the following (in thousands): September 30, 2024 December 31, 2023 Prepaid research and development related expenses $ 4,208 $ 1,822 Tax receivables 1,253 1,752 Prepaid insurance 1,074 1,410 Other 919 846 Total $ 7,454 $ 5,830

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2024
Accrued Liabilities, Current [Abstract]
Accrued Liabilities	9. Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, 2024 December 31, 2023 Accrued accounting, legal, and other professional fees $ 4,540 $ 5,468 Accrued external research and development expenses 3,657 3,031 Accrued payroll 2,350 4,941 Other liabilities 1,114 1,101 Taxes payable 182 715 Accrued restructuring costs 110 — Total $ 11,953 $ 15,256

Leases

Leases	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Leases	10. Leases The Company leases certain office space under long-term operating leases that expire at various dates through 2028. The Company generally has options to renew lease terms on its facilities, which may be exercised at the Company's sole discretion. The Company evaluates renewal and termination options at the lease commencement date to determine if it is reasonably certain to exercise the option and has concluded on all operating leases that is it not reasonably certain that any options will be exercised. The weighted-average remaining lease term for the Company’s operating leases as of September 30, 2024 was 3.6 years. The weighted-average discount rate for the Company’s operating leases as of September 30, 2024 was 12.8 %. ROU assets and lease liabilities related to the Company ’s operating leases are as follows (in thousands): Balance Sheet Classification September 30, 2024 December 31, 2023 Right-of-use assets Operating lease right-of-use asset, net $ 1,032 $ 1,223 Current lease liabilities Current portion of lease liability 257 275 Non-current lease liabilities Non-current portion of lease liability 808 990 Expenses related to leases is recorded on a straight-line basis over the lease term. The following table summarizes lease costs by component for the three and nine months ended September 30, 2024 and 2023 (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease Cost Components Statement of Operations Classification 2024 2023 2024 2023 Operating lease cost Operating expenses: General and administrative $ 87 $ 120 $ 317 $ 431 Short-term lease cost Operating expenses: General and administrative 33 102 110 384 Total lease cost $ 120 $ 222 $ 427 $ 815 Future minimum commitments under all non-cancelable operating leases are as follows (in thousands): Year Ended 2024 (excluding nine months ended September 30, 2024) $ 94 2025 375 2026 375 2027 375 2028 125 Total lease payments 1,344 Less: Imputed interest ( 279 ) Present value of lease liabilities $ 1,065 Supplemental cash flow information related to the Company ’s operating leases for the nine months ended September 30, 2024 and 2023 are as follows (in thousands): 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 326 $ 304 Right-of-use assets obtained in exchange for new operating lease liabilities $ — $ 1,356

Debt

Debt	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Debt	11. Debt Convertible Promissory Notes 2018 Convertible Promissory Notes—Related Parties During November 2018 and October 2020, the Company executed a terms and conditions agreement (the “Convertible Note Agreement”) under which it would issue convertible promissory notes to investors. An investor would become a party to the Convertible Note Agreement and would be issued a convertible promissory note by executing and delivering a subscription form. In November 2018 and October 2020, certain investors subscribed to the Convertible Note Agreement and the Company issued convertible promissory notes in the aggregate principal amount of € 1.0 million or $ 1.2 million (collectively, the “2018 Convertible Notes”). The 2018 Convertible Notes are non-interest-bearing, unsecured and are due and payable on September 30, 2025, unless previously redeemed, converted, purchased or cancelled (the “Maturity Date”). Each 2018 Convertible Note has a face value of €1 and is convertible into one share of ATAI Life Sciences AG upon the payment of € 17.00 . Conversion rights may be exercised by a noteholder at any time prior to maturity, except during certain periods subsequent to the consummation of the IPO. The 2018 Convertible Notes may be declared for early redemption by the noteholders upon occurrence of specified events of default, including payment default, insolvency and a material adverse change in the Company’s business, operations or financial or other condition. Upon early redemption, the conversion right with respect to the 2018 Convertible Notes may no longer be exercised. The Company concluded that both the embedded conversion feature, which is exercisable by the investor at any time during the maturity, and the contingent put option, which would trigger upon the occurrence of an event of default of the 2018 Convertible Notes, do not meet the criteria to be bifurcated and separately accounted for as derivatives and the notes were recorded net of discount and issuance costs, or a reduction to the carrying value of the notes issued in November 2018, with a corresponding adjustment to additional paid in capital. The discount is being amortized using the effective interest method over the period from the respective date of issuance to the Maturity Date. The Company determined that the October 2020 notes were issued in exchange for services previously provided by the Company’s founders and other shareholders and were fully vested and non-forfeitable upon issuance. These instruments were therefore considered stock-based compensation awards to non-employees, and the instruments were initially measured and recorded at their grant date fair value based on a Black-Scholes option pricing model. The fair value of the October 2020 notes exceeded the principal amount that will be due at maturity. Therefore, at initial recognition, the October 2020 notes were accounted for as convertible debt issued at a substantial premium, such that the face value of the note is recorded as a liability and the premium was recorded as paid-in capital. Exchange of 2020 Convertible Promissory Notes In November 2023 and April 2024, a noteholder and a related party noteholder, respectively, of the October 2020 notes and ATAI Life Sciences AG executed exchange agreements (together the "Exchange Agreements") where each noteholder agreed to exchange its 2020 convertible notes issued by ATAI Life Sciences AG ("Old AG Notes") into the same principal amount of new convertible notes issued by ATAI Life Sciences NV ("New NV Notes"). The New NV Notes are non-interest-bearing, unsecured and are due and payable on September 30, 2025, unless previously redeemed, converted, purchased or cancelled (the “Maturity Date”). Each New NV Note has a face value of € 1 and is convertible into sixteen shares of ATAI Life Sciences NV upon the payment of € 17.00 . Conversion rights may be exercised by a noteholder at any time prior to maturity. The New NV Notes may be declared for early redemption by the noteholders upon occurrence of specified events of default, including payment default, insolvency and a material adverse change in the Company’s business, operations or financial or other condition. Upon early redemption, the conversion right with respect to the New NV Notes may no longer be exercised. In December 2023 and April 2024, the Company entered into subscription agreements with each of the noteholder and related party noteholder, respectively (together the "Subscription Agreements") and exchanged their respective Old AG Notes into New NV Notes. The Company determined that the note exchanges were modifications of the debt. The Exchange Agreements and Subscription Agreements resulted in the New NV Notes conversion option no longer meeting the equity classification criteria. Accordingly, at the time of the Exchange Agreements modification, the Company bifurcated the conversion option and reclassified the conversion option fair value from equity to a liability and is included in Convertible promissory notes and derivative liability in the unaudited condensed consolidated balance sheet. The conversion option is measured at fair value on a quarterly basis and any changes in the fair value will be recorded as Change in fair value of assets and liabilities, net, a component of other income (expense), net in the unaudited condensed consolidated statements of operations. For the three and nine months ended September 30, 2024, the Company recognized a gain of $ 1.0 million $ 3.9 million, respectively, as a result of the change in fair value of the New NV Notes. As of September 30, 2024 and December 31, 2023, the fair value of the Convertible promissory note and derivative liability was $ 1.5 million and $ 2.7 million, respectively. As of September 30, 2024 , the fair value of the Short-term convertible promissory note and derivative liability - related party was $ 0.9 million. As of December 31, 2023, the carrying amount and fair value amount of the 2018 Convertible Notes was $ 0.2 million and $ 1.5 million, respectively. Term Loan Hercules Loan and Security Agreement In August 2022 (the “Closing Date”), the Company and certain subsidiaries, as guarantors, and Hercules Capital, Inc., a Maryland corporation (“Hercules”), entered into a Loan and Security Agreement the “Initial Hercules Loan Agreement”. The Initial Hercules Loan Agreement provides for term loans in an aggregate principal amount of up to $ 175.0 million under multiple tranches (as amended by that certain First Amendment to Loan and Security Agreement, dated as of March 13, 2023, the "First Amendment”, that Second Amendment to Loan and Security Agreement, dated as of May 26, 2023, the “Second Amendment,” and that Third Amendment to Loan and Security Agreement, dated August 14, 2024, the “Third Amendment,” and collectively, the “2022 Term Loan Facility”). On May 26, 2023, the Company, ATAI Life Sciences AG (“ATAI AG” and together with the Company, the “Borrowers”) and certain subsidiary guarantors of the Company (collectively, the “Subsidiary Guarantors”) entered into the Second Amendment with the several banks and other financial institutions or entities from time to time parties to the Hercules Loan Agreement, defined below, (collectively, the “Lenders”) and Hercules, in its capacity as administrative agent and collateral agent for itself and for the Lenders (the “Agent”) which amended that certain Loan and Security Agreement, dated August 9, 2022 (as amended by the First Amendment, the “Existing Loan Agreement,” and as amended by the Second Amendment, the “Hercules Loan Agreement”) to, among other things, (i) extend the availability of Tranche 1B of $ 10.0 million, from May 1, 2023, under the Existing Loan Agreement, to November 15, 2024, (ii) extend the availability of Tranche 1C of $ 15.0 million, from December 15, 2023, under the Existing Loan Agreement, to December 15, 2024, (iii) provide Tranche 1D of $ 20.0 million, available upon the earlier of (x) the full draw of Tranche 1C and (y) the expiration of Tranche 1C availability, through February 15, 2025, (iv) extend the availability of Tranche 2 of $ 15.0 million, from June 30, 2024, under the Existing Loan Agreement, subject to certain conditions under the Hercules Loan Agreement, to the earlier of (x) the full draw of Tranche 1D and (y) the expiration of Tranche 1D availability, through March 15, 2025, subject to the Tranche 2 Draw Test, (v) extend the timeline to achieve the second amortization extension condition, from June 30, 2024, in the Existing Loan Agreement, to December 15, 2024, (vi) amend the Tranche 2 Draw Test, satisfaction of which is a condition to draw Tranche 2 under the Hercules Loan Agreement and (vii) extend the financial covenant commencement date, from the later of (x) July 1, 2023, and (y) the date that the outstanding debt under the facility is equal to or greater than $ 40.0 million, in the Existing Loan Agreement, to the later of (x) May 1, 2024, and (y) the date that the outstanding debt under the facility is equal to or greater than $ 30.0 million, provided, that the financial covenant is waived if the Company has a market capitalization of at least $ 550.0 million. On August 14, 2024 (the “Third Amendment Date”), the Borrowers and certain Subsidiary Guarantors” entered into the Third Amendment with the Lenders and Hercules, in its capacity as the Agent, which amended that certain Loan and Security Agreement, dated August 9, 2022 (as amended by the First Amendment, the Second Amendment and the Third Amendment, the “2022 Term Loan Agreement”) to, among other things, (i) provide Tranche 1B of $ 5.0 million on the Third Amendment Date, (ii) reduce the remainder of available Tranche 1 to $ 25.0 million, and extend the availability thereof (x) with respect to Tranche 1C, to be available after the Third Amendment Date until March 31, 2025, and (y) with respect to Tranche 1D, to be available upon the earlier to occur of (1) March 31, 2025 and (2) full borrowing of Tranche 1C, until June 30, 2025, (iii) increase Tranche 2 to $ 30.0 million, and extend the availability thereof to be available upon the earlier to occur of (1) June 30, 2025, and (2) full borrowing of Tranche 1D, until September 30, 2025, subject to the Tranche 2 Draw Test, (iv) extend the availability of Tranche 3 of $ 100.0 million, through March 31, 2026, available subject to lender’s investment committee approval, (v) extend the amortization date to September 1, 2025, and extend the timeline to achieve the second amortization extension condition, to June 30, 2025, upon the occurrence of which the amortization date may be extended to March 1, 2026, (vi) amend the financial covenant to commence on October 1, 2024, and require that so long as the Company’s market capitalization is less than $ 550.0 million, Borrowers shall maintain qualified cash equal to at least 50 % of the sum of (x) the amount of outstanding debt under the facility plus (y) Qualified Cash A/P Amount (as defined in the Agreement), or upon the occurrence of certain conditions, 70 % of the sum of (x) the amount of outstanding debt under the facility plus (y) Qualified Cash A/P Amount, and (vii) reduce the interest rate to equal the greater of (x) 9.05 % or (y) prime rate plus 4.30 % (or, upon achieving certain conditions, (y) shall equal prime rate plus 4.05 %). The 2022 Term Loan Facility will mature on August 1, 2026 (the “Maturity Date”), which may be extended until February 1, 2027 if the Company raises at least $ 175.0 million of unrestricted new net cash proceeds from certain permitted sources after the Closing Date and prior to June 30, 2025, and satisfies certain other specified conditions (the “Extension Condition Two”). The outstanding principal balance of the 2022 Term Loan Facility bears interest at a floating interest rate per annum equal to the greater of either (i) the prime rate as reported in the Wall Street Journal plus 4.30 % and (ii) 9.05 %; provided, that if the Extension Condition Two is satisfied, the rate of interest in the foregoing clause (i) is prime rate as reported in The Wall Street Journal plus 4.05 %. Accrued interest is payable monthly following the funding of each term loan advance. The Company may make payments of interest only, without any loan amortization payments, until September 1, 2025, which date may be extended to (i) March 1, 2026 if Extension Condition Two is achieved. At the end of the interest only period, the Company is required to begin repayment of the outstanding principal of the 2022 Term Loan Facility in equal monthly installments. The 2022 Term Loan Agreement contains customary closing and commitment fees, prepayment fees and provisions, events of default and representations, warranties and affirmative and negative covenants, including a financial covenant requiring the Company to maintain certain levels of cash in accounts subject to a control agreement in favor of the Agent (the “Qualified Cash”) at all times commencing from the Closing Date, which includes a cap on the amount of cash that can be held by, among others, certain of our foreign subsidiaries in Australia and the United Kingdom. In addition, the financial covenant under the 2022 Term Loan Agreement requires that beginning on October 1, 2024, the Company shall maintain Qualified Cash in an amount no less than the sum of (1) 50 % of the outstanding amount under the 2022 Term Loan Facility, and (2) the amount of the Borrowers’ and Subsidiary Guarantors’ accounts payable that have not been paid within 180 days from the invoice date of the relevant account payable, subject to certain exceptions; provided, upon the occurrence of certain conditions, the Company shall at all times maintain Qualified cash in an amount no less than the sum of (1) 70 % of the outstanding amount under the 2022 Term Loan Facility, and (2) the amount of the Borrowers’ and Subsidiary Guarantors’ accounts payable that have not been paid within 180 days from the invoice date of the relevant account payable, subject to certain exceptions; provided, further, that the financial covenant shall not apply on any day that the Company's market capitalization is at least $ 550.0 million measured on a consecutive 10-business day period immediately prior to such date of measurement and tested on a daily basis. Upon the occurrence of an event of default, including a material adverse effect, subject to certain exceptions, on the Company and ATAI AG’s, taken together, business, operations, properties, assets or financial condition, and subject to any specified cure periods, all amounts owed by the Company may be declared immediately due and payable by the Lenders. As of September 30, 2024, the Company was in compliance with all applicable covenants under the 2022 Term Loan Agreement. In addition, the Company is required to make a final payment fee (the “End of Term Charge”) upon the earlier of (i) the Maturity Date, (ii) the date that the Company prepays, in full or in part, the principal balance of the 2022 Term Loan Facility, or (iii) the date that the outstanding balance of the 2022 Term Loan Facility becomes due and payable. The End of Term Charge is 6.95 % of the aggregate original principal amount of the term loans so repaid or prepaid under the 2022 Term Loan Agreement. The Company may, at its option, prepay the term loans in full or in part, subject to a prepayment penalty equal to (i) 2.00 % of the principal amount prepaid if the prepayment occurs on or prior to the first anniversary of the Closing Date, (ii) 1.0 % of the principal amount prepaid if the prepayment occurs after the first anniversary and on or prior to the second anniversary of the Closing Date, and (iii) 0.5 % of the principal amount prepaid if the prepayment occurs after the second anniversary and prior to the Maturity Date. The Company incurred financing expenses related to the 2022 Term Loan Agreement, which are recorded as an offset to long-term debt on the Company's consolidated balance sheets. These deferred financing costs are being amortized over the term of the debt using the effective interest method, and are included in other income, net in the Company’s unaudited condensed consolidated statements of operations. During the three months ended September 30, 2024 and 2023, interest expense included $ 0.1 million and $ 0.1 million of am ortized deferred financing costs related to the 2022 Term Loan Facility. During the nine months ended September 30, 2024 and 2023, interest e xpense included $ 0.3 million and $ 0.3 million of am ortized deferred financing costs related to the 2022 Term Loan Facility. Outstanding debt obligations are as follows (in thousands): September 30, 2024 December 31, 2023 Principal amount $ 20,000 $ 15,000 End of the term charge 1,042 1,042 Less: unamortized issuance discount ( 144 ) ( 204 ) Less: unamortized issuance costs ( 60 ) ( 84 ) Less: unamortized end of term charge ( 502 ) ( 707 ) Net carrying amount 20,336 15,047 Less: current maturities — — Long-term debt, net of current maturities and unamortized debt discount and issuance costs $ 20,336 $ 15,047 The fair value of the outstanding debt obligations under the 2022 Term Loan Facility was $ 20.4 million as of September 30, 2024 , and $ 16.2 million as of December 31, 2023 , respectively. The fair value of the debt obligations under the 2022 Term Loan Facility represent Level 3 measurements within the fair value hierarchy.

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity Note [Abstract]
Common Stock	12. Common Stock All common shareholders have identical rights. Each common share entitles the holder to one vote on all matters submitted to the shareholders for a vote. All holders of common shares are entitled to receive dividends, as may be declared by the Company’s board of supervisory directors. Upon liquidation, common shareholders will receive distribution on a pro rata basis. As of September 30, 2024 and December 31, 2023, no cash dividends have been declared or paid. In November 2022, the Company entered into an Open Market Sale Agreement with Jefferies LLC (“Jefferies”), pursuant to which the Company may issue and sell its common shares, nominal value € 0.10 per share, having an aggregate offering price of up to $ 150,000,000 , from time to time through an “at the market” equity offering program under which Jefferies will act as sales agent. There have been no sales under the Sales Agreement through September 30, 2024 .

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	13. Stock-Based Compensation atai Equity Incentive Plans The Company has options and restricted stock units (“RSUs”) outstanding under various equity incentive plans, including the 2020 Incentive Plan, 2021 Incentive Plan, defined below, and HSOP Plan, which are further described in Note 13 of the Company’s audited consolidated financial statements included in the Company’s Annual Report on Form 10-K filed with the SEC on March 28, 2024. As of September 30, 2024, there were no shares available for future grants under the 2020 Incentive Plan and any shares subject to outstanding options originally granted under the 2020 Equity Incentive Plan that terminate, expire or lapse for any reason without the delivery of shares to the holder thereof shall become available for issuance pursuant to the atai Life Sciences N.V. 2021 Incentive Award Plan (the "2021 Incentive Plan"). Shares that are expired, terminated, surrendered, or canceled without having been fully exercised will be available for future awards. As of September 30, 2024 , 40,791,437 shares were available for future grants under the 2021 Incentive Plan. As of September 30, 2024 , 257,419 HSOP Options were available for future grants under the HSOP Plan. Stock Option activity under 2020 Incentive Plan and 2021 Incentive Plan The stock options outstanding noted below consist primarily of both service and performance-based options to purchase common stock. These stock options have a five-year or ten-year contractual term. These awards are subject to the risk of forfeiture until vested by virtue of continued employment or service to the Company. The following is a summary of stock option activity from December 31, 2023 to September 30, 2024: Number of Weighted- Weighted- Aggregate Outstanding as of December 31, 2023 39,066,454 $ 4.62 5.56 $ 6,294 Granted 10,783,294 (1) 1.75 — — Exercised ( 322,857 ) 2.06 — — Cancelled or forfeited ( 7,589,498 ) 5.35 — — Outstanding as of September 30, 2024 41,937,393 (2) $ 3.78 5.82 $ 3,367 Options exercisable as of September 30, 2024 23,616,028 $ 4.69 3.76 $ 3,350 (1) Includes (a) 7,757,000 stock options with 25 % vesting on January 1, 2025 and the remaining over a three-year service period, (b) 1,016,094 stock options that will vest upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares, (c) 1,083,200 stock options that will vest over a four-year service period, (d) 515,000 stock options that will vest after a one-year service period, and (e) 412,000 stock options with 33 % vesting on the first anniversary of the grant date and the remaining over a two-year service period. (2) The 18,321,366 outstanding unvested stock options includes (a) 9,199,618 stock options that will continue to vest over a one to four-year service period, (b) 7,013,000 options with 25 % vesting on January 1, 2025 and the remaining over a three-year service period, (c) 1,016,094 stock options that will vest upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares, (d) 992,654 that will continue to vest over a three to four-year service period and upon the satisfaction of specified performance-based vesting conditions, and (e) 100,000 stock options that will continue to vest over a two-year service period and upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares. The weighted-average grant-date fair value of options granted during the nine months ended September 30, 2024 was $ 1.19 . The weighted-average grant-date fair value of options granted during the nine months ended September 30, 2023 was $ 0.97 . The Company estimates the fair value of each stock option using the Black-Scholes option-pricing model on the date of grant. During the nine months ended September 30, 2024, the assumptions used in the Black-Scholes option pricing model were as follows: September 30, 2024 2023 Weighted average expected term in years 5.95 6.15 Weighted average expected stock price volatility 73.9 % 87.5 % Risk-free interest rate 3.78 % - 4.40 % 3.50 % - 4.09 % Expected dividend yield 0 % 0 % For the three months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of $ 4.6 million and $ 6.9 million, respectively. For the nine months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of $ 15.5 million and $ 21.6 million, respectively. As of September 30, 2024 , total unrecognized compensation cost related to the unvested stock options was $ 23.6 million, which is expected to be recognized over a weighted average period of 2.03 years. Restricted Stock Unit activity under the 2021 Incentive Plan The restricted stock units noted below consist of service-based awards vesting over a two-year period, subject to the risk of forfeiture until vested by virtue of continued employment or service to the Company. The Company reflects restricted stock units as issued and outstanding common stock when vested and the shares have been delivered to the individual. The following is a summary of restricted stock unit activity from December 31, 2023 to September 30, 2024: Restricted Stock Units Weighted Average Grant Date Fair Value Unvested at December 31, 2023 2,944,935 $ 1.18 Granted — — Vested 1,469,063 1.18 Forfeited 348,815 1.18 Unvested at September 30, 2024 1,127,057 $ 1.18 For the three months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of $ 0.5 million and $ 0.5 million, respectively. For the nine months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of $ 1.3 million and $ 1.0 million, respectively. The total fair value of restricted stock units vested during the nine months ended September 30, 2024 was $ 1.7 million. As of September 30, 2024 , total unrecognized compensation cost related to the unvested stock-based awards was $ 0.5 million, which is expected to be recognized over a weighted average period of 0.40 years. Stock Option activity under HSOP Plan The HSOP Options outstanding noted below consist of service and performance-based options to request the distribution of HSOP Shares. These HSOP Options have a fifteen-year contractual term. These HSOP Options vest over a three to four-year service period. These awards are subject to the risk of forfeiture until vested by virtue of continued employment or service to the Company. The following is a summary of stock option acti vity from December 31, 2023 to September 30, 2024: Number of Weighted- Weighted- Aggregate Outstanding as of December 31, 2023 6,921,829 $ 6.64 12.01 $ — Granted — — — — Exercised — — — — Cancelled or forfeited — — — — Outstanding as of September 30, 2024 6,921,829 $ 6.64 11.34 $ — Options exercisable as of September 30, 2024 6,921,829 $ 6.64 11.34 $ — For the three months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of zero and $ 0.7 million, respectively. For the nine months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of $ 0.1 million and $ 2.5 million, respectively. As of September 30, 2024 , there was no unrecognized compensation cost related to the unvested stock-based awards. Subsidiary Equity Incentive Plans Certain controlled subsidiaries of the Company adopted their own equity incentive plans (each, an “EIP”). Each EIP is generally structured so that the applicable subsidiary, and its affiliates’ employees, directors, officers and consultants are eligible to receive non-qualified and incentive stock options and restricted stock unit awards under their respective EIP. Standard option grants have time-based vesting requirements, generally vesting over a period of four years with a contractual term of ten years. Such time-based stock options use the Black-Scholes option pricing model to determine grant date fair value. For the three months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of an immaterial amount and $ 0.1 million, respectively, in relation to subsidiary EIPs. For the nine months ended September 30, 2024 and 2023 , the Company recorded stock-based compensation expense of $ 0.1 million and $ 0.3 million, respectively, in relation to subsidiary EIPs. As of September 30, 2024 , there was an immaterial amount of total unrecognized stock-based compensation expense related to unvested EIP awards to employees and non-employee directors expected to be recognized over a weighted-average period of approximately 0.89 years. Stock-Based Compensation Stock-based compensation expense is allocated to either research and development or general and administrative expense on the unaudited condensed consolidated statements of operations based on the cost center to which the option holder belongs. The following table summarizes the total stock-based compensation expense by function for the three and nine months ended September 30, 2024, which includes expense related to stock options and restricted stock unit awards (in thousands): Three months ended September 30, 2024 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 1,949 $ — $ 15 $ 1,964 General and administrative 3,082 — — $ 3,082 Total stock-based compensation expense $ 5,031 $ — $ 15 $ 5,046 For the nine months ended September 30, 2024 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 6,317 $ — $ 135 $ 6,452 General and administrative 10,506 117 13 $ 10,636 Total stock-based compensation expense $ 16,823 $ 117 $ 148 $ 17,088 The following table summarizes the total stock-based compensation expense by function for the three and nine months ended September 30, 2023, which includes expense related to stock options and restricted stock unit awards (in thousands): Three months ended September 30, 2023 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 3,285 $ — $ 107 $ 3,392 General and administrative 4,110 744 7 $ 4,861 Total stock-based compensation expense $ 7,395 $ 744 $ 114 $ 8,253 For the nine months ended September 30, 2023 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 9,866 $ — $ 320 $ 10,186 General and administrative 12,947 2,512 33 $ 15,492 Total stock-based compensation expense $ 22,813 $ 2,512 $ 352 $ 25,677

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes The Company records its quarterly income tax expense by utilizing an estimated annual effective tax rate applied to its period to date earnings as adjusted for any discrete items arising during the quarter. The tax effect for discrete items are recorded in the period in which they occur. The Company recorded a $ 0.2 million income tax benefit and a $ 0.2 million income tax expense for the three months ended September 30, 2024 and 2023, respectively. The Company recorded a $ 0.2 million income tax benefit and a $ 0.6 million income tax expense for the nine months ended September 30, 2024 and 2023, respectively. The decrease in income tax expense shown in 2024 was primarily driven by a reduction in global earnings, a favorable return to provision from one of the Company's Australian subsidiaries, and the release of an uncertain tax liability associated with a 2021 subsidiary tax return. The primary difference between the effective tax rate and the statutory tax rate relates to the income tax treatment of stock compensation expense, which impacts the current and overall tax expense due to the applicable valuation allowance. The Company continues to maintain a full valuation allowance against its deferred tax assets.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	15. Net Loss Per Share Basic and diluted net loss per share attributable to atai stockholders were calculated as follows (in thousands, except share and per share data): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 Basic EPS Numerator: Net income (loss) $ ( 26,311 ) $ 43,371 $ ( 111,058 ) $ ( 24,753 ) Net loss attributable to noncontrolling interests ( 25 ) ( 873 ) ( 747 ) ( 2,821 ) Net income (loss) attributable to ATAI Life Sciences N.V. shareholders — basic (numerator) $ ( 26,286 ) $ 44,244 $ ( 110,311 ) $ ( 21,932 ) Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. Shareholders (denominator) 160,621,817 155,792,490 159,973,201 155,793,601 Net income (loss) per common share attributable to ATAI Life Sciences N.V. Shareholders - basic $ ( 0.16 ) $ 0.28 $ ( 0.69 ) $ ( 0.14 ) Diluted EPS Net income (loss) $ ( 26,311 ) $ 43,371 $ ( 111,058 ) $ ( 24,753 ) Net loss attributable to noncontrolling interests ( 25 ) ( 873 ) ( 747 ) ( 2,821 ) Net income (loss) attributable to ATAI Life Sciences N.V. shareholders — diluted (numerator) $ ( 26,286 ) $ 44,244 $ ( 110,311 ) $ ( 21,932 ) Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. Shareholders 160,621,817 155,792,490 159,973,201 155,793,601 Effect of dilutive securities: Options to purchase common stock — 12,426,724 — — Unvested restricted stock units — 3,144,935 — — 2018 Convertible Promissory Note - Related Parties (note 11) — 6,201,824 — — Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. shareholders (denominator) 160,621,817 177,565,973 159,973,201 155,793,601 Net income (loss) per common share attributable to ATAI Life Sciences N.V. shareholders — diluted $ ( 0.16 ) $ 0.25 $ ( 0.69 ) $ ( 0.14 ) HSOP Shares issued to the Partnership and allocated to the HSOP Participants are not considered outstanding for accounting purposes and not included in the calculation of basic weighted average common shares outstanding in the table above because the HSOP Participants have a forfeitable right to distributions until the HSOP Options vest and are exercised, at which time the right becomes nonforfeitable. The following also represents the maximum amount of outstanding shares of potentially dilutive securities that were excluded from the computation of diluted net loss per share attributable to common shareholders for the periods presented because including them would have been antidilutive: As of September 30, 2024 2023 Options to purchase common stock 41,937,393 27,974,365 HSOP options to purchase common stock 6,921,829 6,921,829 2018 short-term convertible promissory notes - related parties 2,367,200 — 2018 short-term convertible promissory notes 3,818,704 — Unvested restricted stock units 1,127,057 — 56,172,183 34,896,194

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. Commitments and Contingencies Research and Development Agreements The Company may enter into contracts in the ordinary course of business with clinical research organizations for clinical trials, with contract manufacturing organizations for clinical supplies and with other vendors for preclinical studies, supplies and other services and products for operating purposes. Indemnification In the ordinary course of business, the Company may provide indemnifications of varying scope and terms to vendors, lessors, business partners, board members, officers and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, services to be provided by the Company, negligence or willful misconduct of the Company, violations of law by the Company, or intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with directors and certain officers and employees that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors, officers or employees. No demands have been made upon the Company to provide indemnification under such agreements, and thus, there are no claims that the Company is aware of that could have a material effect on the Company’s unaudited condensed consolidated financial statements. The Company also maintains director and officer insurance, which may cover certain liabilities arising from its obligation to indemnify the Company’s directors. To date, the Company has not incurred any material costs and has not accrued any liabilities in the unaudited condensed consolidated financial statements as a result of these provisions. Contingencies From time to time, the Company may become involved in legal proceedings arising in the ordinary course of business. The Company is unable to predict the outcome of these matters or the ultimate legal and financial liability, and at this time cannot reasonably estimate the possible loss or range of loss and accordingly has not accrued a related liability. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company accrues a liability when a loss is considered probable and the amount can be reasonably estimated. When a material loss contingency is reasonably possible but not probable, the Company does not record a liability, but instead discloses the nature and the amount of the claim, and an estimate of the loss or range of loss, if such an estimate can be made. Legal fees are expensed as incurred.

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2024
License Agreements [Abstract]
License Agreements	17. License Agreements Otsuka License and Collaboration Agreement In March 2021, Perception entered into a license and collaboration agreement (the “Otsuka Agreement”) with Otsuka under which Perception granted exclusive rights to Otsuka to develop and commercialize products containing arketamine, known as PCN-101 in Japan for the treatment of any depression, including treatment-resistant depression, or major depressive disorder or any of their related symptoms or conditions at its own cost and expense. Perception retained all rights to PCN-101 outside of Japan. With the execution of the Otsuka Agreement, Perception received an upfront, non-refundable payment of $ 20.0 million. Perception is also entitled to receive aggregate payments of up to $ 35.0 million if certain development and regulatory milestones are achieved for the current or a new intravenous formulation of a product and up to $ 66.0 million in commercial milestones upon the achievement of certain commercial sales thresholds. Otsuka is obligated to pay Perception a tiered, double-digit royalty on net sales of products containing PCN-101 in Japan, subject to reduction in certain circumstances. For the three and nine months ended September 30, 2024 and 2023, respectively, there were no milestones achieved under the Otsuka Agreement. For the three months ended September 30, 2024 and 2023 , respectively, the company recognized an immaterial amount and $ 0.1 million of license revenue related to certain research and development services. For the nine months ended September 30, 2024 and 2023 , respectively, the company recognized $ 0.3 million and $ 0.3 million of license revenue related to certain research and development services. National University Corporation Chiba University License Agreement In August 2017, Perception entered into a license agreement (the “CHIBA License”), with the National University Corporation Chiba University (“CHIBA”), relating to Perception’s drug discovery and development initiatives. Under the CHIBA License, Perception has been granted a worldwide exclusive license under certain patents and know-how of CHIBA to research, develop, manufacture, use and commercialize therapeutic products. During the three and nine months ended September 30, 2024 and 2023 , respectively, the Company made no material payments pursuant to the CHIBA License. Allergan License Agreement In February 2020, Recognify entered into an amended and restated license agreement (the “Allergan License Agreement”), with Allergan Sales, LLC (“Allergan”), under which Allergan granted Recognify an exclusive (non-exclusive as to know-how), sublicensable and worldwide license under certain patent rights and know-how controlled by Allergan to develop, manufacture and commercialize certain products for use in all fields including the treatment of certain diseases and conditions of the central nervous system. During the three and nine months ended September 30, 2024 and 2023 , respectively, Recognify made no material payments pursuant to the Allergan License Agreement. Columbia Stock Purchase and License Agreement In June 2020, Kures, Inc. ("Kures") entered into a license agreement with Trustees of Columbia University (“Columbia”), pursuant to which, Kures obtained an exclusive license under certain patents and technical information to discover, develop, manufacture, use and commercialize such patents or other products in all uses and applications (“Columbia IP”). In addition, in consideration for the rights to the Columbia IP, Kures entered into a Stock Purchase Agreement (the “SPA”) with Columbia in contemplation of the license agreement. Pursuant to the SPA, Kures issued to Columbia certain shares of the Kures’ capital stock, representing 5.0 % of Kures common stock on a fully diluted basis. Furthermore, the SPA provided that from time to time, Kures shall issue to Columbia additional shares of Kures’ common stock, at a per share price equal to the then fair market value of each such share, which price shall be deemed to have been paid in partial consideration for the execution, delivery and performance by Columbia of the License Agreement, such that the common stock held by Columbia shall equal to 5.0 % of the common stock on a fully diluted basis, at all times up to and through the achievement of certain funding threshold. During the three and nine months ended September 30, 2024 and 2023, respectively, Kures made no material payments or share issuances in connection with the Columbia agreement. Dalriada License Agreement In December 2021, Invyxis, Inc. (“Invyxis”), a wholly owned subsidiary of the Company, entered into an exclusive services and license agreement (the “Invyxis ESLA”) with Dalriada Drug Discovery Inc. (“Dalriada”). Under the Invyxis ESLA, Dalriada is to exclusively collaborate with Invyxis to develop products, services and processes with the specific purpose of generating products consisting of new chemical entities. Invyxis will pay Dalriad a up to $ 12.8 millio n in service fees for research and support services. In addition, Invyxis will pay Dalriada success milestone payments and low single digit royalty payments based on net product sales. Invyxis has the right, but not the obligation, to settle future royalty payments based on net product sales with the Company's common stock. Invyxis and Dalriada will determine the equity settlement based on a price per share determined by both parties. In January 2022, in accordance with the Invyxis ESLA, Invyxis paid an upfront deposit of $ 1.1 million, which was capitalized as prepaid research and development expense. In December 2022, the Company executed an amendment to the Invyxis ESLA, which reduced the upfront deposit from $ 1.1 million to $ 0.5 million. As such, the remaining $ 0.6 million was applied against research and development expense incurred. The Company will expense the remaining deposit as the services are performed as a component of research and development expense in the consolidated statements of operations. As of September 30, 2024, the upfront deposit has been applied against research and development expenses in the consolidated statement of operations. During the three months ended September 30, 2024 and 2023 , respectively, the Company recorded an immaterial amount and $ 0.4 million as research and development expense in the unaudited condensed consolidated statement of operations. During the nine months ended September 30, 2024 and 2023, respectively, the Company recorded $ 0.4 million and $ 1.5 million as research and development expense in the unaudited condensed consolidated statements of operations. For the three and nine months ended September 30, 2024 and 2023 , respectively, Invyxis made no other service fee payments to Dalriada.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	18. Related Party Transactions atai Formation In connection with the formation of atai in 2018, the Company entered into a series of transactions with its shareholders, Apeiron, Galaxy Group Investments LLC. (“Galaxy”) and HCS Beteiligungsgesellschaft mbH (“HCS”) whereby these shareholders contributed their investments in COMPASS, Innoplexus and Juvenescence to the Company in exchange for the Company's common stock of equivalent value. Apeiron is the family office of the Company’s co-founder who owns 20.2 % and 19.7 % of the outstanding common stock in the Company as of September 30, 2024 and December 31, 2023 , respectively. Galaxy is a NYC-based multi-strategy investment firm that owns 6.4 % and 6.5 % of the outstanding common stock in the Company as of September 30, 2024 and December 31, 2023, respectively. Directed Share Program In connection with the Company's initial public offering, the underwriters reserved 27 % of the common shares for sale at the initial offering price to the Company’s managing directors, supervisory directors and certain other parties. Apeiron participated in the program and purchased $ 10.5 million common shares. Consulting Agreement with Mr. Angermayer In January 2021, the Company entered into a consulting agreement, (the “Consulting Agreement”), with Mr. Angermayer, one of the Company’s co-founders and supervisory director. Apeiron is the family office and merchant banking business of Mr. Angermayer. Pursuant to the Consulting Agreement, Mr. Angermayer agreed to render services to the Company on business and financing strategies in exchange for 624,000 shares under the 2020 Incentive Plan upon achievement of certain performance targets. In January 2024, the Company and Mr. Angermayer entered into the Termination and New Consultancy Agreement (the “2024 Consultancy Agreement"). Pursuant to the 2024 Consultancy Agreement, the parties agreed to terminate the Consulting Agreement (as defined above) between ATAI AG and Mr. Angermayer dated January 16, 2021 (the “Original Consultancy Agreement”) and enter into a new consultancy agreement between the Company and Mr. Angermayer to, among other things, extend the term of the Original Consultancy Agreement to January 5, 2028, increase the services to include various business objectives (including related to business and finance, communication and investor relations), and provide for the grant of an option to purchase 1,658,094 shares of the Company that vests over four years in part based on continued service and in part based on the Company's total shareholder return compared to the four-year total shareholder return of the companies comprising the XBI. As a result of the 2024 Consulting Agreement, for the three and nine months ended September 30, 2024 , the Company recorded $ 0.1 million and $ 0.3 million, respectively, of stock-based compensation included in general and administrative expense in its unaudited condensed consolidated statements of operations. Additionally, as a result of the Consulting Agreement, for the three and nine months ended September 30, 2023 , the Company recorded $ 0.2 million and $ 0.6 million, respectively, of stock-based compensation included in general and administrative expense in its unaudited condensed consolidated statements of operations. For the three and nine months ended September 30, 2024 , the Company recorded an immaterial amount and $ 0.3 million, respectively, of stock-based compensation included in general and administrative expense in its unaudited condensed consolidated statements of operations related to Mr. Angermayer's service as Chairman of the Company's board of supervisory directors. Additionally, for the three and nine months ended September 30, 2023 , the Company recorded $ 0.1 million and $ 0.4 million, respectively, of stock-based compensation included in general and administrative expense in its unaudited condensed consolidated statements of operations related to Mr. Angermayer's service as Chairman of the Company's board of supervisory directors.

Defined Contribution Plan

Defined Contribution Plan	9 Months Ended
	Sep. 30, 2024
Retirement Benefits [Abstract]
Defined Contribution Plan	19. Defined Contribution Plan The Company has a defined contribution retirement savings plan under Section 401(k) of the Internal Revenue Code. This plan allows eligible employees to defer a portion of their annual compensation. Employees may make contributions by having the Company withhold a percentage of their salary up to the Internal Revenue Service annual limit. The Company recogn ized $ 0.1 million and $ 0.1 million of related compensation expense for the three months ended September 30, 2024 and 2023 . Additionally, the Company recognized $ 0.3 million and $ 0.4 million of related compensation expense for the nine months ended September 30, 2024 and 2023.

Corporate Restructuring

Corporate Restructuring	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Corporate Restructuring	20. Corporate Restructuring 2024 Restructuring In February 2024, the Company restructured its workforce and eliminated approximately 10 % of its global workforce in order to more effectively allocate its research and development and other resources supporting the revised business and program priorities and to reduce operational costs. Restructuring expense related to the workforce reduction incurred during the nine months ended September 30, 2024, resulted in $ 2.0 million of restructuring expense, which consisted of $ 1.6 million o f cash expenditures for severance and other employee separation-related costs and $ 0.4 million of stock-based compensation expense. Of the restructuring expense, for the nine months ended September 30, 2024, $ 0.3 million and $ 1.7 million were recorded in research and development expenses and general and administrative expenses, respectively, in the unaudited condensed consolidated statement of operations. The Company recorded an immaterial amount of restructuring expense for the three months ended September 30, 2024. As of September 30, 2024, net restructuring liabilities totaled approximately $ 0.1 million included in accrued expenses on the Company's unaudited condensed consolidated balance sheets. 2023 Restructuring In February 2023, the Company restructured its workforce and eliminated approximately 30 % of its global workforce in order to more effectively allocate its research and development and other resources supporting the revised business and program priorities and to reduce operational costs. Restructuring expense related to the workforce reduction incurred during the nine months ended September 30, 2023 , resulted in $ 3.2 million of restructuring expense, which consisted of $ 3.0 million of cash expenditures for severance and other employee separation-related costs and $ 0.2 million of stock-based compensation expense. Of the restructuring expense, for the nine months ended September 30, 2023 , $ 1.8 million and $ 1.4 million were recorded in research and development expenses and general and administrative expenses, respectively, in the unaudited condensed consolidated statement of operations. As of September 30, 2023, all restructuring liabilities had been paid in full and there were no restructuring liabilities included in accrued expenses on the Company's unaudited condensed consolidated balance sheets. A reconciliation of the restructuring charges and related payments for the nine months ended September 30, 2024 and 2023 is as follows: As of September 30, 2024 2023 Restructuring costs expensed during the period $ 2,026 $ 3,206 Non-cash impact of stock-based compensation ( 358 ) ( 195 ) Cash payments of restructuring liabilities, net ( 1,558 ) ( 3,011 ) Ending Restructuring liability $ 110 $ —

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	21. Subsequent Events In October 2024, the Company acquired all of the issued and outstanding shares of IntelGenx Corp., a subsidiary of IntelGenx Technologies Corp., following the approval and vesting order obtained on September 30, 2024 from the Superior Court of Québec (Commercial Division) issued in connection with the proceedings instituted pursuant to the CCAA. No Company equity or cash was exchanged in connection with this transaction. In October 2024, pursuant to the terms of the Beckley Psytech Escrow Agreement, Beckley Psytech, at its sole discretion, drew $ 5.0 million from the escrow account and the Company was credited 3,012,048 Series C shares.

Basis of Presentation, Consol_2

Basis of Presentation, Consolidation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and follow the requirements of the United States Securities and Exchange Commission (“SEC”) for interim financial reporting. Accordingly, these unaudited condensed consolidated financial statements do not include all of the information and disclosures required by U.S. GAAP for complete financial statements as certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on March 28, 2024. The unaudited condensed consolidated financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the Company’s financial position, its results of operations and comprehensive loss, and its cash flows for the periods presented. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 or for any other future annual or interim period. Any reference in these notes to applicable accounting guidance is meant to refer to the authoritative U.S. GAAP included in the Accounting Standards Codification (“ASC”), and Accounting Standards Update (“ASU”) issued by the Financial Accounting Standards Board (“FASB”). Reclassifications Certain reclassifications were made to prior period amounts in the unaudited condensed consolidated financial statements and accompanying notes to conform with current year presentation in order to consolidate and simplify the disclosures of changes in assets and liabilities held at fair value. Consolidation The Company's unaudited condensed consolidated financial statements include the accounts of atai and its subsidiaries. All intercompany balances and transactions have been eliminated in the consolidation. The Company's policy is to consolidate all entities that it controls by ownership of a majority of the outstanding voting stock. In addition, entities that meet the definition of a variable interest entity (“VIE”) for which atai is the primary beneficiary are consolidated. The primary beneficiary is the party who has the power to direct the activities of a VIE that most significantly impact the entity’s economic performance and who has an obligation to absorb losses of the entity or a right to receive benefits from the entity that could potentially be significant to the entity. For consolidated entities that are less than wholly-owned, the third-party’s holding of equity interest is presented as Noncontrolling interests in the Company's unaudited condensed consolidated balance sheets and unaudited condensed consolidated statements of stockholders' equity. The portion of net earnings attributable to the noncontrolling interests is presented as Net loss attributable to noncontrolling interests in the Company's unaudited condensed consolidated statements of operations. Ownership interests in entities over which the Company has significant influence, but not a controlling financial interest, are accounted for under either the alternative measurement under ASC 321 or as an equity method investment. Investments eligible for the measurement alternative under ASC 321 are carried at its initial cost, with remeasurements to fair value upon impairment or upon a price change observed in an orderly transaction of the same or similar investment of the same issuer . For equity method investments where the Company has not elected the fair value option, it records gains (losses) from investments in equity method investees, net of tax, for its proportionate share of the underlying company’s net results until the investment balance is adjusted to zero. If the Company makes subsequent additional investments in that same company, it may record additional gains (losses) based on changes to its investment basis and also may record additional income (loss) in equity method investments. If the Company has elected the fair value option for an equity investment, the fair value of the investment will be recorded upon acquisition and any changes in fair value will be recorded as a component of other income (expense), net.
Significant Accounting Policies	Significant Accounting Policies During the nine months ended September 30, 2024, there were no significant changes to the Company’s significant accounting policies as described in the Company’s audited consolidated financial statements as of and for the year ended December 31, 2023 exc ept as described below.
Restricted Cash	Restricted Cash The Company maintains certain cash balances restricted as to withdrawal or use. Restricted cash assets as of September 30, 2024 are for the sole purpose of purchasing additional Series C Shares in Beckley Psytech Limited. See Note 5 for further information.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements ASU 2016-13 Financial Instruments - Credit Losses In June 2016, the FASB issued ASU 2016-13, Financial Instruments — Credit Losses. This guidance requires immediate recognition of management’s estimates of current expected credit losses. Under the prior model, losses were recognized only when losses were deemed probable. The new model is applicable to most financial assets and certain other instruments that are not measured at fair value through net income. The Company utilizes an undiscounted probability-of-default (“PD”) and loss-given-default (“LGD”) method for estimating credit losses on its assets pool, which is comprised of loans to other companies. Under the PD and LGD method, the expected credit loss percentage (or “loss rate”) is calculated as the probability of default (i.e., the probability the asset will default within the given time frame) multiplied by the loss given default (i.e., the percentage of the asset not expected to be collected because of default). To implement the PD and LGD method, the Company utilizes readily observable market information from term-matched public debt to derive market implied current expected credit losses (“MICECL”) grouped by Standard & Poor’s (“S&P”) credit rating scale. The MICECL framework considers risk characteristics of assets pool based on publicly available or estimated S&P credit ratings to calculate an appropriate credit loss reserve for the pool or group of assets. ASU 2016-13 requires a cumulative effect adjustment to the statement of financial position as of the beginning of the first reporting period in which it is effective. On January 1, 2023, the Company adopted this guidance and applied a modified-retrospective transition approach through a cumulative-effect adjustment to retained earnings upon adoption. At transition, the new accounting guidance’s adoption resulted in an increase to accumulated deficit of $ 0.5 million, net of tax attributable to an increase in the allowance for credit losses related to its l ong-term notes receivable - related parties. Further, the FASB issued ASU 2019-04, ASU 2019-05, ASU 2019-11, ASU 2020-03 and ASU 2022-02 to provide additional clarification and guidance on the credit losses standard. The Company adopted ASU 2019-04, ASU 2019-05, ASU 2019-11, ASU 2020-03 and ASU 2022-02 on January 1, 2023. The adoption of these standards did not have a material impact on the Company’s consolidated financial statements or disclosures.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standard Board ("FASB") issued new guidance designed to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant expenses per segment. The guidance is effective for all fiscal years beginning after December 15, 2023, and for interim periods beginning after December 15, 2024. The new standard must be adopted on a retrospective basis and early adoption is permitted. The Company is not early adopting the standard. We are currently evaluating this guidance to determine its impact on our consolidated financial statements. In December 2023, the FASB issued new guidance designed to improve income tax disclosure requirements, primarily through increased disaggregation disclosures within the effective tax rate reconciliation as well as enhanced disclosures on income taxes paid. The guidance is effective for all fiscal years beginning after December 15, 2024. The new standard can be adopted on a prospective basis with an option to be adopted retrospectively and early adoption is permitted. The Company is not early adopting the standard. We are currently evaluating this guidance to determine its impact on our consolidated financial statements. In November 2024, the FASB issued new guidance designed to improve income statement expense disclosures, primarily by requiring new financial statement disclosures in tabular format and disaggregating information about prescribed categories underlying any relevant income statement captions. The standard is effective for fiscal years beginning after December 15, 2026 and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. Upon adoption, the new standard may be applied prospectively or retrospectively. The Company is currently evaluating the impact that the adoption may have on its disclosures in its condensed consolidated financial statements.

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Primary Beneficiary for VIEs Consolidated Under the VIE Model	As of September 30, 2024 and December 31, 2023, the Company has accounted for the following consolidated investments as VIEs: Consolidated Entities Relationship as of Relationship as of Date Control Obtained Ownership % September 30, 2024 Ownership % December 31, 2023 Perception Neuroscience Holdings, Inc. Controlled VIE Controlled VIE November 2018 59.2 % 59.2 % Kures, Inc. Controlled VIE Controlled VIE August 2019 64.5 % 64.5 % Recognify Life Sciences, Inc. Controlled VIE Controlled VIE November 2020 51.9 % 51.9 % PsyProtix, Inc. Wholly-Owned Subsidiary Controlled VIE February 2021 100.0 % 75.0 %
Summary of the Assets and Liabilities for all Consolidated VIEs	The following table presents the assets and liabilities (excluding intercompany balances that were eliminated in consolidation) for all VIEs as of September 30, 2024 (in thousands): Perception Kures Recognify Assets: Current assets: Cash $ 89 $ 26 $ 2,508 Accounts receivable 313 — — Prepaid expenses and other current assets 5 37 62 Total current assets 407 63 2,570 Total assets $ 407 $ 63 $ 2,570 Liabilities: Current liabilities: Accounts payable $ 236 $ 375 $ 565 Accrued liabilities 352 174 2,222 Other current liabilities 40 — 3 Total current liabilities 628 549 2,790 Total liabilities $ 628 $ 549 $ 2,790 The following table presents the assets and liabilities (excluding intercompany balances that were eliminated in consolidation) for all consolidated VIEs as of December 31, 2023 (in thousands): Perception Kures Recognify PsyProtix Assets: Current assets: Cash $ 97 $ 257 $ 4,356 $ 35 Accounts receivable 84 — — — Prepaid expenses and other current assets 257 — 450 — Total current assets 438 257 4,806 35 Long-term notes receivable — — — 97 Other assets — — — — Total assets $ 438 $ 257 $ 4,806 $ 132 Liabilities: Current liabilities: Accounts payable $ 31 $ 329 $ 1,926 $ — Accrued liabilities 718 84 609 26 Other current liabilities 12 — 1 — Total current liabilities 761 413 2,536 26 Total liabilities $ 761 $ 413 $ 2,536 $ 26
Schedule of Non Controlling Interest Recognized to Its Consolidated VIEs Roll Forward	The Company recognizes noncontrolling interests related to its consolidated VIEs and provides a roll forward of the noncontrolling interests balance, as follows (in thousands): Perception Kures Recognify Total Balance as of December 31, 2023 $ 428 $ 369 $ 557 $ 1,354 Net loss attributable to noncontrolling interests - preferred ( 100 ) ( 25 ) ( 539 ) ( 665 ) Comprehensive income attributable to noncontrolling interests 17 7 — 24 Balance as of March 31, 2024 $ 345 $ 350 $ 18 $ 713 Net loss attributable to noncontrolling interests - preferred ( 36 ) ( 4 ) ( 18 ) ( 57 ) Comprehensive loss attributable to noncontrolling interests ( 9 ) ( 4 ) — ( 13 ) Balance as of June 30, 2024 $ 300 $ 343 $ — $ 643 Net loss attributable to noncontrolling interests - preferred ( 38 ) 13 — ( 25 ) Comprehensive loss attributable to noncontrolling interests ( 15 ) ( 6 ) — ( 22 ) Balance as of September 30, 2024 $ 247 $ 349 $ — $ 596 Perception Kures Recognify Total Balance as of December 31, 2022 $ 1,731 $ 451 $ 2,844 $ 5,026 Net loss attributable to noncontrolling interests - preferred ( 700 ) ( 93 ) ( 426 ) ( 1,219 ) Comprehensive loss attributable to noncontrolling interests 6 2 — 8 Balance as of March 31, 2023 $ 1,037 $ 360 $ 2,418 $ 3,815 Net loss attributable to noncontrolling interests - preferred ( 266 ) ( 32 ) ( 431 ) ( 729 ) Comprehensive income (loss) attributable to noncontrolling interests ( 1 ) 2 — 1 Balance as of June 30, 2023 $ 770 $ 330 $ 1,987 $ 3,087 Net loss attributable to noncontrolling interests - preferred ( 320 ) 65 ( 618 ) ( 873 ) Comprehensive income (loss) attributable to noncontrolling interests 17 5 — 22 Balance as of September 30, 2023 $ 467 $ 400 $ 1,369 $ 2,236

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investment	As of September 30, 2024 and December 31, 2023, the carrying values of Other investments, which consisted of investments in the investee’s preferred stock not in the scope of ASC 323 were as follows (in thousands): September 30, 2024 December 31, 2023 Beckley Psytech Limited $ 33,893 $ — GABA Therapeutics, Inc. — 1,838 Innoplexus AG — — Total $ 33,893 $ 1,838
Schedule Of Equity Method Investment Summarized Balance Sheet	The following is a summary of financial data for investments accounted for under the equity method of accounting (in thousands): Balance Sheets September 30, 2024 December 31, 2023 GABA GABA Current assets $ 181 $ 1,720 Total assets $ 181 $ 1,720 Current liabilities $ 2,330 $ 1,546 Total liabilities $ 2,330 $ 1,546
Shedule Of Equity Method Investment Summarized Statement Of Operations	Statements of operations For the three months ended September 30, 2024 For the three months ended September 30, 2023 GABA GABA Loss from continuing operations $ ( 623 ) $ ( 238 ) Net loss $ ( 623 ) $ ( 238 ) For the nine months ended September 30, 2024 For the nine months ended September 30, 2023 GABA GABA Loss from continuing operations $ ( 2,597 ) $ ( 3,199 ) Net loss $ ( 2,597 ) $ ( 3,199 )

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Summary of Fair Value Measurement on Recurring Basis	The following table presents information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis and indicates the fair value hierarchy of the valuation (in thousands): Fair Value Measurements as of September 30, 2024 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 829 $ — $ — $ 829 Investment in securities at fair value: U.S. treasuries — 51,358 — 51,358 U.S. government agencies — 4,599 — 4,599 Other investments held at fair value 43,506 — 1,721 45,227 Short-term notes receivable - related party, net — — 5,700 5,700 $ 44,335 $ 55,957 $ 7,421 $ 107,713 Liabilities: Other current liability $ — $ — $ 147 $ 147 Contingent consideration liability - related parties — — 650 650 Contingent consideration liability — — 1,388 1,388 2018 convertible promissory note conversion option - related party — — 758 758 2018 convertible promissory note conversion option — — 1,239 1,239 $ — $ — $ 2,796 $ 2,796 Fair Value Measurements as of December 31, 2023 Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 56 $ — $ — $ 56 Investment in securities at fair value: U.S. treasuries — 67,119 — 67,119 Corporate notes/bonds — 5,007 — 5,007 U.S. government agencies — 37,097 — 37,097 Other investments held at fair value 83,701 — 6,124 89,825 Convertible notes receivable - related party — — 11,202 11,202 $ 83,757 $ 109,223 $ 17,326 $ 210,306 Liabilities: Contingent consideration liability - related parties $ — $ — $ 620 $ 620 Contingent consideration liability — — 1,637 1,637 2018 convertible promissory note conversion option — — 2,385 2,385 $ — $ — $ 4,643 $ 4,643
Summary of Fair Value Measurement Inputs and Valuation Techniques	The fair value of the Perception contingent consideration liability – related parties was calculated using the following significant unobservable inputs: September 30, 2024 December 31, 2023 Valuation Technique Significant Unobservable Inputs Input Range Input Range Discounted cash flow Milestone contingent consideration: Discount rate 11.3 % 13.5 % Probability of the milestone 28.0 % 28.0 % Discounted cash flow with Scenario-Based Method Royalty contingent consideration: Discount rate for royalties 11.0 %- 12.7 % 13.0 % - 14.2 % Discount rate for royalties on milestones 11.0 %- 12.7 % 13.0 % - 14.2 % Probability of success rate 28.0 % 13.4 % - 28.0 %
Summary of Fair Value Measurement on Recurring Basis, Unobservable Input Reconciliation	The following table provides a roll forward of the aggregate fair values of the Company’s financial instruments described above, for which fair value is determined using Level 3 inputs (in thousands): IntelGenx Debt (1) IntelGenx Investments Held at Fair Value (2) IntelGenx Subsequent DIP Loan Commitment Contingent (3) Contingent (4) New NV Notes Conversion Feature Beckley Psytech Additional Warrants Balance as of December 31, 2023 $ 11,202 $ 6,124 $ — $ 620 $ 1,637 $ 2,385 $ — Initial fair value of instrument 988 420 — — — — 2,645 Change in fair value, including interest 1,712 1,429 — ( 13 ) ( 231 ) 1,734 — Balance as of March 31, 2024 $ 13,902 $ 7,973 $ — $ 607 $ 1,406 $ 4,119 $ 2,645 Initial fair value of instrument 3,425 — 680 — — 3,590 — Change in fair value, including interest ( 7,455 ) ( 7,973 ) — ( 27 ) ( 32 ) ( 4,780 ) 720 Balance as of June 30, 2024 $ 9,872 $ — $ 680 $ 580 $ 1,373 $ 2,929 $ 3,364 Initial fair value of instrument $ 3,830 — — — — — — Additional Warrants received $ — — — — — — ( 1,538 ) Change in fair value, including interest $ ( 8,002 ) — ( 533 ) 70 15 ( 932 ) ( 105 ) Balance as of September 30, 2024 $ 5,700 $ — $ 147 $ 650 $ 1,388 $ 1,997 $ 1,721 Convertible notes receivable - related party IntelGenx 2023 Initial Warrants Contingent Balance as of December 31, 2022 $ — $ — $ 953 Initial fair value of instrument — — — Change in fair value — — ( 35 ) Extinguishment of liability — — — Balance as of March 31, 2023 $ — $ — $ 918 Initial fair value of instrument — Change in fair value — — ( 76 ) Extinguishment of liability — — — Balance as of June 30, 2023 $ — $ — $ 842 Initial fair value of instrument 1,497 724 — Change in fair value, including interest 22 — 58 Extinguishment of liability — — — Balance as of September 30, 2023 $ 1,519 $ 724 $ 900 (1) Includes the IntelGenx Term Loan, the 2023 Initial Notes, the 2023 Subsequent Notes, the DIP Loan, and the 2023 Term Loan Note. (2) Includes the 2023 Initial Warrants, the 2023 Subsequent Warrants, the 2024 Warrants, and the Call Option Units. (3) Includes Perception milestone based contingent consideration liability. (4) Includes contingent consideration liability related to DemeRx IB Stock Purchase and contingent consideration liability related to the TryptageniX research and development milestone success fee payments and royalties payments.
DemeRx IB, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Summary of Fair Value Measurement Inputs and Valuation Techniques	The fair value of the DemeRx contingent consideration liability – related parties was calculated using the following significant unobservable inputs: September 30, 2024 December 31, 2023 Valuation Technique Significant Unobservable Inputs Input Range Input Range Discounted cash flow Milestone contingent consideration: Discount rate 11.3 %- 11.4 % 13.9 % Probability of the milestone 20.0 % - 25.0 % 20.0 % - 25.0 %

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2024
Prepaid Expense and Other Assets, Current [Abstract]
Summary of prepaid expenses and other current assets	Prepaid expenses consist of the following (in thousands): September 30, 2024 December 31, 2023 Prepaid research and development related expenses $ 4,208 $ 1,822 Tax receivables 1,253 1,752 Prepaid insurance 1,074 1,410 Other 919 846 Total $ 7,454 $ 5,830

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2024
Accrued Liabilities, Current [Abstract]
Summary of accrued liabilities	Accrued liabilities consist of the following (in thousands): September 30, 2024 December 31, 2023 Accrued accounting, legal, and other professional fees $ 4,540 $ 5,468 Accrued external research and development expenses 3,657 3,031 Accrued payroll 2,350 4,941 Other liabilities 1,114 1,101 Taxes payable 182 715 Accrued restructuring costs 110 — Total $ 11,953 $ 15,256

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Schedule of operating leases assets and liabilities lessee	ROU assets and lease liabilities related to the Company ’s operating leases are as follows (in thousands): Balance Sheet Classification September 30, 2024 December 31, 2023 Right-of-use assets Operating lease right-of-use asset, net $ 1,032 $ 1,223 Current lease liabilities Current portion of lease liability 257 275 Non-current lease liabilities Non-current portion of lease liability 808 990
Components of expenses related to leases is recorded on a straight-line basis over the lease term	The following table summarizes lease costs by component for the three and nine months ended September 30, 2024 and 2023 (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease Cost Components Statement of Operations Classification 2024 2023 2024 2023 Operating lease cost Operating expenses: General and administrative $ 87 $ 120 $ 317 $ 431 Short-term lease cost Operating expenses: General and administrative 33 102 110 384 Total lease cost $ 120 $ 222 $ 427 $ 815
Schedule of future minimum commitments maturity operating leases	Future minimum commitments under all non-cancelable operating leases are as follows (in thousands): Year Ended 2024 (excluding nine months ended September 30, 2024) $ 94 2025 375 2026 375 2027 375 2028 125 Total lease payments 1,344 Less: Imputed interest ( 279 ) Present value of lease liabilities $ 1,065
Schedule of supplemental cash flow information related to operating leases	Supplemental cash flow information related to the Company ’s operating leases for the nine months ended September 30, 2024 and 2023 are as follows (in thousands): 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 326 $ 304 Right-of-use assets obtained in exchange for new operating lease liabilities $ — $ 1,356

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Schedule of Outstanding debt obligations	Outstanding debt obligations are as follows (in thousands): September 30, 2024 December 31, 2023 Principal amount $ 20,000 $ 15,000 End of the term charge 1,042 1,042 Less: unamortized issuance discount ( 144 ) ( 204 ) Less: unamortized issuance costs ( 60 ) ( 84 ) Less: unamortized end of term charge ( 502 ) ( 707 ) Net carrying amount 20,336 15,047 Less: current maturities — — Long-term debt, net of current maturities and unamortized debt discount and issuance costs $ 20,336 $ 15,047

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Share-based Payment Arrangement, Option, Activity	The following is a summary of stock option activity from December 31, 2023 to September 30, 2024: Number of Weighted- Weighted- Aggregate Outstanding as of December 31, 2023 39,066,454 $ 4.62 5.56 $ 6,294 Granted 10,783,294 (1) 1.75 — — Exercised ( 322,857 ) 2.06 — — Cancelled or forfeited ( 7,589,498 ) 5.35 — — Outstanding as of September 30, 2024 41,937,393 (2) $ 3.78 5.82 $ 3,367 Options exercisable as of September 30, 2024 23,616,028 $ 4.69 3.76 $ 3,350 (1) Includes (a) 7,757,000 stock options with 25 % vesting on January 1, 2025 and the remaining over a three-year service period, (b) 1,016,094 stock options that will vest upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares, (c) 1,083,200 stock options that will vest over a four-year service period, (d) 515,000 stock options that will vest after a one-year service period, and (e) 412,000 stock options with 33 % vesting on the first anniversary of the grant date and the remaining over a two-year service period. (2) The 18,321,366 outstanding unvested stock options includes (a) 9,199,618 stock options that will continue to vest over a one to four-year service period, (b) 7,013,000 options with 25 % vesting on January 1, 2025 and the remaining over a three-year service period, (c) 1,016,094 stock options that will vest upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares, (d) 992,654 that will continue to vest over a three to four-year service period and upon the satisfaction of specified performance-based vesting conditions, and (e) 100,000 stock options that will continue to vest over a two-year service period and upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares.
Summary of Employee Stock Ownership Plan (ESOP) Disclosures	The following is a summary of stock option acti vity from December 31, 2023 to September 30, 2024: Number of Weighted- Weighted- Aggregate Outstanding as of December 31, 2023 6,921,829 $ 6.64 12.01 $ — Granted — — — — Exercised — — — — Cancelled or forfeited — — — — Outstanding as of September 30, 2024 6,921,829 $ 6.64 11.34 $ — Options exercisable as of September 30, 2024 6,921,829 $ 6.64 11.34 $ —
Shedule of Restricted Stock Unit Activity	The following is a summary of restricted stock unit activity from December 31, 2023 to September 30, 2024: Restricted Stock Units Weighted Average Grant Date Fair Value Unvested at December 31, 2023 2,944,935 $ 1.18 Granted — — Vested 1,469,063 1.18 Forfeited 348,815 1.18 Unvested at September 30, 2024 1,127,057 $ 1.18
Share-based Payment Arrangement, Expensed and Capitalized, Amount	The following table summarizes the total stock-based compensation expense by function for the three and nine months ended September 30, 2024, which includes expense related to stock options and restricted stock unit awards (in thousands): Three months ended September 30, 2024 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 1,949 $ — $ 15 $ 1,964 General and administrative 3,082 — — $ 3,082 Total stock-based compensation expense $ 5,031 $ — $ 15 $ 5,046 For the nine months ended September 30, 2024 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 6,317 $ — $ 135 $ 6,452 General and administrative 10,506 117 13 $ 10,636 Total stock-based compensation expense $ 16,823 $ 117 $ 148 $ 17,088 The following table summarizes the total stock-based compensation expense by function for the three and nine months ended September 30, 2023, which includes expense related to stock options and restricted stock unit awards (in thousands): Three months ended September 30, 2023 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 3,285 $ — $ 107 $ 3,392 General and administrative 4,110 744 7 $ 4,861 Total stock-based compensation expense $ 7,395 $ 744 $ 114 $ 8,253 For the nine months ended September 30, 2023 atai 2020 and 2021 Incentive Plans atai Other Subsidiaries Equity Plan Total Research and development $ 9,866 $ — $ 320 $ 10,186 General and administrative 12,947 2,512 33 $ 15,492 Total stock-based compensation expense $ 22,813 $ 2,512 $ 352 $ 25,677
Two Thousand And Twenty Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The Company estimates the fair value of each stock option using the Black-Scholes option-pricing model on the date of grant. During the nine months ended September 30, 2024, the assumptions used in the Black-Scholes option pricing model were as follows: September 30, 2024 2023 Weighted average expected term in years 5.95 6.15 Weighted average expected stock price volatility 73.9 % 87.5 % Risk-free interest rate 3.78 % - 4.40 % 3.50 % - 4.09 % Expected dividend yield 0 % 0 %

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Basis and Diluted Net Loss Per Share Attributable to ATAI Stockholders	Basic and diluted net loss per share attributable to atai stockholders were calculated as follows (in thousands, except share and per share data): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 Basic EPS Numerator: Net income (loss) $ ( 26,311 ) $ 43,371 $ ( 111,058 ) $ ( 24,753 ) Net loss attributable to noncontrolling interests ( 25 ) ( 873 ) ( 747 ) ( 2,821 ) Net income (loss) attributable to ATAI Life Sciences N.V. shareholders — basic (numerator) $ ( 26,286 ) $ 44,244 $ ( 110,311 ) $ ( 21,932 ) Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. Shareholders (denominator) 160,621,817 155,792,490 159,973,201 155,793,601 Net income (loss) per common share attributable to ATAI Life Sciences N.V. Shareholders - basic $ ( 0.16 ) $ 0.28 $ ( 0.69 ) $ ( 0.14 ) Diluted EPS Net income (loss) $ ( 26,311 ) $ 43,371 $ ( 111,058 ) $ ( 24,753 ) Net loss attributable to noncontrolling interests ( 25 ) ( 873 ) ( 747 ) ( 2,821 ) Net income (loss) attributable to ATAI Life Sciences N.V. shareholders — diluted (numerator) $ ( 26,286 ) $ 44,244 $ ( 110,311 ) $ ( 21,932 ) Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. Shareholders 160,621,817 155,792,490 159,973,201 155,793,601 Effect of dilutive securities: Options to purchase common stock — 12,426,724 — — Unvested restricted stock units — 3,144,935 — — 2018 Convertible Promissory Note - Related Parties (note 11) — 6,201,824 — — Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. shareholders (denominator) 160,621,817 177,565,973 159,973,201 155,793,601 Net income (loss) per common share attributable to ATAI Life Sciences N.V. shareholders — diluted $ ( 0.16 ) $ 0.25 $ ( 0.69 ) $ ( 0.14 )
Schedule of Computation of Diluted net Income (Loss) Per Share Attributable to Common Shareholders	As of September 30, 2024 2023 Options to purchase common stock 41,937,393 27,974,365 HSOP options to purchase common stock 6,921,829 6,921,829 2018 short-term convertible promissory notes - related parties 2,367,200 — 2018 short-term convertible promissory notes 3,818,704 — Unvested restricted stock units 1,127,057 — 56,172,183 34,896,194

Corporate Restructuring (Tables

Corporate Restructuring (Tables)	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Schedule Of Reconciliation Of The Restructuring Charges And Related Payments	A reconciliation of the restructuring charges and related payments for the nine months ended September 30, 2024 and 2023 is as follows: As of September 30, 2024 2023 Restructuring costs expensed during the period $ 2,026 $ 3,206 Non-cash impact of stock-based compensation ( 358 ) ( 195 ) Cash payments of restructuring liabilities, net ( 1,558 ) ( 3,011 ) Ending Restructuring liability $ 110 $ —

Organization and Description _2

Organization and Description of Business - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Short-term debt securities	$ 56,000
Cash and cash equivalents	29,963	$ 45,034
Restricted cash	15,000
Accumulated deficit	$ (661,249)	$ (550,938)

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Jan. 01, 2023
Accounting Policies [Line Items]
Operating lease right-of-use asset, net	$ 1,032	$ 1,223
Current portion of lease liability	$ 257	$ 275
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Operating lease right-of-use asset, net	Operating lease right-of-use asset, net
Noncurrent portion of lease liability	$ 808	$ 990
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Noncurrent portion of lease liability	Noncurrent portion of lease liability
Cumulative Effect, Period of Adoption, Adjustment [Member]
Accounting Policies [Line Items]
Accumulated Deficit Net Of Tax			$ 500

Acquisitions and Dispositions -

Acquisitions and Dispositions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Business Combinations [Line Items]
Non-operating income expense	$ (3,861)	$ 70,681	$ (36,795)	$ 70,944
Psyber, Inc. [Member]
Business Combinations [Line Items]
Non-operating income expense			300
TryptageniX, Inc [Member]
Business Combinations [Line Items]
Non-operating income expense			$ 400

Variable Interest Entities - Ad

Variable Interest Entities - Additional information (Detail) - USD ($) $ in Millions	Sep. 30, 2024	Apr. 30, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 15		$ 6.1
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure			0.1
Long term notes receivable
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 5.7		$ 11.2
GABA Options [Member]
Variable Interest Entity [Line Items]
Equity method investment, ownership percentage		100%
Minimum [Member] | PsyProtix, Inc. [Member]
Variable Interest Entity [Line Items]
Equity method investment, ownership percentage		25%

Variable Interest Entities - Su

Variable Interest Entities - Summary of Primary Beneficiary for VIEs Consolidated Under the VIE Model (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Perception Neuroscience Holdings, Inc. [Member]
Variable Interest Entity [Line Items]
Relationship	Controlled VIE	Controlled VIE
Date Control Obtained	November 2018
Ownership %	59.20%	59.20%
Kures, Inc. [Member]
Variable Interest Entity [Line Items]
Relationship	Controlled VIE	Controlled VIE
Date Control Obtained	August 2019
Ownership %	64.50%	64.50%
Recognify Life Sciences, Inc. [Member]
Variable Interest Entity [Line Items]
Relationship	Controlled VIE	Controlled VIE
Date Control Obtained	November 2020
Ownership %	51.90%	51.90%
PsyProtix, Inc. [Member]
Variable Interest Entity [Line Items]
Relationship	Wholly-Owned Subsidiary	Controlled VIE
Date Control Obtained	February 2021
Ownership %	100%	75%

Variable Interest Entities - _2

Variable Interest Entities - Summary of the Assets and Liabilities for all Consolidated VIEs (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Prepaid expenses and other current assets	$ 7,454	$ 5,830
Total current assets	114,074	185,592
Long term notes receivable	0	97
Other assets	2,428	2,720
Total assets	197,519	293,478
Current liabilities:
Accounts payable	4,880	4,589
Accrued liabilities	11,953	15,256
Other current liabilities	147	0
Total current liabilities	19,643	20,120
Total liabilities	51,203	49,162
Perception [Member]
Current assets:
Cash	89	97
Accounts receivable	313	84
Prepaid expenses and other current assets	5	257
Total current assets	407	438
Long term notes receivable		0
Other assets		0
Total assets	407	438
Current liabilities:
Accounts payable	236	31
Accrued liabilities	352	718
Other current liabilities	40	12
Total current liabilities	628	761
Total liabilities	628	761
Kures [Member]
Current assets:
Cash	26	257
Accounts receivable	0	0
Prepaid expenses and other current assets	37	0
Total current assets	63	257
Long term notes receivable		0
Other assets		0
Total assets	63	257
Current liabilities:
Accounts payable	375	329
Accrued liabilities	174	84
Other current liabilities	0	0
Total current liabilities	549	413
Total liabilities	549	413
Recognify [Member]
Current assets:
Cash	2,508	4,356
Accounts receivable	0	0
Prepaid expenses and other current assets	62	450
Total current assets	2,570	4,806
Long term notes receivable		0
Other assets		0
Total assets	2,570	4,806
Current liabilities:
Accounts payable	565	1,926
Accrued liabilities	2,222	609
Other current liabilities	3	1
Total current liabilities	2,790	2,536
Total liabilities	$ 2,790	2,536
PsyProtix [Member]
Current assets:
Cash		35
Accounts receivable		0
Prepaid expenses and other current assets		0
Total current assets		35
Long term notes receivable		97
Other assets		0
Total assets		132
Current liabilities:
Accounts payable		0
Accrued liabilities		26
Other current liabilities		0
Total current liabilities		26
Total liabilities		$ 26

Variable Interest Entities - Sc

Variable Interest Entities - Schedule of Non Controlling Interest Recognized to Its Consolidated VIEs Roll Forward (Detail) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023
Noncontrolling Interest [Line Items]
Opening balance	$ 643	$ 713	$ 1,354	$ 3,087	$ 3,815	$ 5,026
Net loss attributable to noncontrolling interests - preferred	(25)	(57)	(665)	(873)	(729)	(1,219)
Comprehensive income (loss) attributable to noncontrolling interests	(22)	(13)	24	22	1	8
Closing balance	596	643	713	2,236	3,087	3,815
Perception [Member]
Noncontrolling Interest [Line Items]
Opening balance	300	345	428	770	1,037	1,731
Net loss attributable to noncontrolling interests - preferred	(38)	(36)	(100)	(320)	(266)	(700)
Comprehensive income (loss) attributable to noncontrolling interests	(15)	(9)	17	17	(1)	6
Closing balance	247	300	345	467	770	1,037
Kures [Member]
Noncontrolling Interest [Line Items]
Opening balance	343	350	369	330	360	451
Net loss attributable to noncontrolling interests - preferred	13	(4)	(25)	65	(32)	(93)
Comprehensive income (loss) attributable to noncontrolling interests	(6)	(4)	7	5	2	2
Closing balance	349	343	350	400	330	360
Recognify [Member]
Noncontrolling Interest [Line Items]
Opening balance	0	18	557	1,987	2,418	2,844
Net loss attributable to noncontrolling interests - preferred	0	(18)	(539)	(618)	(431)	(426)
Comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0	0	0
Closing balance	$ 0	$ 0	$ 18	$ 1,369	$ 1,987	$ 2,418

Investments - Summary of Equity

Investments - Summary of Equity Method Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Aug. 31, 2023	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Carrying Amount of the Investment	$ 0	$ 0		$ 0
COMPASS Pathways Plc Two [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			15.40%
Innoplexus AG [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage					35%
GABA Therapeutics Inc [Member]
Schedule of Equity Method Investments [Line Items]
Carrying Amount of the Investment	$ 0				$ 0

Investments - Summary of Equi_2

Investments - Summary of Equity Method Investments and Other Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Investment [Line Items]
Other Long-term Investments	$ 33,893	$ 1,838
Beckley Psytech Limited [Member]
Investment [Line Items]
Other Long-term Investments	33,893	0
Innoplexus AG [Member]
Investment [Line Items]
Other Long-term Investments	0	0
GABA Therapeutics Inc [Member]
Investment [Line Items]
Other Long-term Investments	$ 0	$ 1,838

Investments - Summary of financ

Investments - Summary of financial data for investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Shedule Of Equity Method Investment Summarized Balance Sheet [Line Items]
Total current assets	$ 114,074	$ 185,592
Total assets	197,519	293,478
Current liabilities	19,643	20,120
Total liabilities	51,203	49,162
GABA Therapeutics Inc [Member]
Shedule Of Equity Method Investment Summarized Balance Sheet [Line Items]
Total current assets	181	1,720
Total assets	181	1,720
Current liabilities	2,330	1,546
Total liabilities	$ 2,330	$ 1,546

Investments - Summary of Statem

Investments - Summary of Statements of operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Shedule Of Equity Method Investment Summarized Statement Of Operations [Line Items]
Revenue	$ 40	$ 87	$ 313	$ 296
Net income (loss)	(26,311)	43,371	(111,058)	(24,753)
GABA Therapeutics Inc [Member]
Shedule Of Equity Method Investment Summarized Statement Of Operations [Line Items]
Loss from continuing operations	(623)	(238)	(2,597)	(3,199)
Net income (loss)	$ (623)	$ (238)	$ (2,597)	$ (3,199)

Investments - COMPASS Pathways

Investments - COMPASS Pathways plc (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Aug. 31, 2023
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value	$ 0.9	$ 1.8	$ 3.2	$ 3.3
Non-cash Loss on Sale	2.1
Compass Pathways Plc [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value	3.9	$ 69	22	$ 69
Market value of the Company's ownership	$ 43.5		$ 43.5		$ 83.7
Compass Pathways Plc [Member] | American Depositary Share [Member]
Cash and Cash Equivalents [Line Items]
Number of share sold			2,660,000
Price per share	$ 6.05		$ 6.05
Net proceed received			$ 16.1
COMPASS Pathways Plc Two [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, ownership percentage						15.40%
COMPASS Pathways Plc Two [Member] | Compass Pathways Plc [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value	$ 3.9

Investments - IntelGenx Technol

Investments - IntelGenx Technologies Corp. (Additional information) (Detail)				1 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	May 31, 2021 USD ($) $ / shares	Nov. 30, 2020 USD ($)	May 31, 2024 USD ($) shares	Nov. 30, 2020 USD ($)	Aug. 31, 2019 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Mar. 15, 2024 USD ($)	Jan. 18, 2024 USD ($) $ / shares shares	Jan. 18, 2024 € / shares	Jan. 05, 2024 USD ($) $ / shares	Jan. 03, 2024 USD ($) $ / shares shares	Jan. 03, 2024 € / shares	Dec. 31, 2023 USD ($)	Nov. 30, 2023 USD ($)	Aug. 31, 2023	Nov. 30, 2022 € / shares	Jun. 30, 2022	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Cash and Cash Equivalents [Line Items]
Equity Method Investments							$ 0		$ 0								$ 0					$ 0
Losses from investments in equity method investees, net of tax							(26,000)	$ (238,000)	(2,000,000)	$ (3,199,000)
Change in fair value of other investments held at fair value							(900,000)	(1,800,000)	(3,200,000)	(3,300,000)
Carrying Amount of the Investment							0		0								0					$ 0
Short term restricted cash for other investments							15,000,000		15,000,000								0
Other Investments held at fair value							45,227,000		45,227,000								$ 89,825,000
Compass Pathways Plc [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value							(3,900,000)	(69,000,000)	(22,000,000)	(69,000,000)
GABA Inc [Member]
Cash and Cash Equivalents [Line Items]
Percentage of voting interest acquired																					50%
IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value							0	0	0	0
Investment measured at fair value as per fair value option		$ 12,300,000																$ 800,000
Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Share price | € / shares																				€ 0.1
Common Stock [Member] | IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Investment measured at fair value as per fair value option							3,000,000		3,000,000
Warrant [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value							(700,000)		(700,000)
Warrant [Member] | IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Common shares		$ 12,300,000
Investment measured at fair value as per fair value option							1,200,000		1,200,000		$ 0
Unit [Member] | IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Investment measured at fair value as per fair value option							$ 8,200,000		$ 8,200,000
Securities Purchase Agreement [Member] | IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Percentage of voting interest acquired							25%		25%
Securities Purchase Agreement [Member] | Warrant [Member] | IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Business acquisition, Share price | $ / shares		$ 0.35
Number of years determining units purchase		3 years
Call Option [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value							$ (5,200,000)		$ (5,200,000)
Subscription and Shareholders' Agreement [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of assets and liabilities							$ 100,000		600,000
Subscription and Shareholders' Agreement [Member] | Warrant [Member]
Cash and Cash Equivalents [Line Items]
Warrants at fair value				$ 1,500,000					$ 1,700,000
Secondary Sale [Member]
Cash and Cash Equivalents [Line Items]
Investment Owned Balance Principal Amount												$ 35,000,000
Innoplexus AG [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investment, Ownership Percentage																							35%
Innoplexus AG [Member] | Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investment, Ownership Percentage							35%		35%								35%
Innoplexus AG [Member] | Innoplexus SPA [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, Proceeds									$ 22,300,000
COMPASS Pathways Plc Two [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investment, Ownership Percentage																			15.40%
COMPASS Pathways Plc Two [Member] | Compass Pathways Plc [Member]
Cash and Cash Equivalents [Line Items]
Change in fair value of other investments held at fair value							$ (3,900,000)
GABA Therapeutics Inc [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investments							0		0														$ 0
Losses from investments in equity method investees, net of tax							200,000	$ 200,000	2,000,000	$ 3,200,000
Carrying Amount of the Investment							$ 0		$ 0														$ 0
GABA Therapeutics Inc [Member] | Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investment, Ownership Percentage							7.20%		7.20%								3.60%
GABA Therapeutics Inc [Member] | Additional Shares [Member]
Cash and Cash Equivalents [Line Items]
Payments to acquire investments			$ 2,000
GABA Therapeutics Inc [Member] | Amended GABA PSPA | Preferred Stock [Member] | Series A Preferred Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investment, Ownership Percentage						20%
Payments to acquire investments		$ 600,000				$ 5,500,000
GABA Therapeutics Inc [Member] | Amended GABA PSPA | Common Stock [Member] | Series A Preferred Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investments							$ 900,000		$ 900,000
Payments to acquire investments	$ 600,000								10,000,000
Carrying Amount of the Investment							900,000		900,000
GABA Therapeutics Inc [Member] | Amended GABA PSPA | Additional Shares [Member] | Series A Preferred Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investments		1,500,000
Carrying Amount of the Investment		$ 1,500,000
GABA Therapeutics Inc [Member] | Omnibus Amendment Agreement [Member]
Cash and Cash Equivalents [Line Items]
Payments to acquire investments					$ 1,800,000
Beckley Psytech Limited [Member]
Cash and Cash Equivalents [Line Items]
Investment Owned Share Capital															50%
Beckley Psytech Limited [Member] | Series C Shares [Member] | Maximum [Member]
Cash and Cash Equivalents [Line Items]
Purchase of Warrants | shares															24,096,385
Beckley Psytech Limited [Member] | Series C Warrants [Member]
Cash and Cash Equivalents [Line Items]
Exercise price, warrants | $ / shares															$ 2.158
Beckley Psytech Limited [Member] | Warrant [Member]
Cash and Cash Equivalents [Line Items]
Purchase of Warrants | shares				4,393,400
Beckley Psytech Limited [Member] | Warrant [Member] | Series C Shares [Member]
Cash and Cash Equivalents [Line Items]
Purchase of Warrants | shares															24,096,385
Beckley Psytech Limited [Member] | Additional Warrants [Member]
Cash and Cash Equivalents [Line Items]
Exercise price, warrants | $ / shares															$ 1.66
Beckley Psytech Limited [Member] | Deferred Shares [Member]
Cash and Cash Equivalents [Line Items]
Share price | $ / shares														$ 1.66
Draw down amount from escrow account							5,000,000		5,000,000					$ 5,000,000
Long term restricted cash for other investments							$ 10,000,000		$ 10,000,000
Beckley Psytech Limited [Member] | Subscription and Shareholders' Agreement [Member] | Series C preferred shares [Member]
Cash and Cash Equivalents [Line Items]
Share price | € / shares																€ 0.0001
Investment owned number of shares | shares															24,096,385
Purchase price of investment															$ 40,000,000
Beckley Psytech Limited [Member] | Share Purchase Deed [Member] | Series C preferred shares [Member]
Cash and Cash Equivalents [Line Items]
Investment owned number of shares | shares							11,153,246		11,153,246
Purchase price of investment															$ 10,000,000
Beckley Psytech Limited [Member] | Escrow Agreement [Member] | Series C Shares [Member]
Cash and Cash Equivalents [Line Items]
Investment owned number of shares | shares															15,060,241
Exercise price, warrants | $ / shares															$ 1.66
Payment made for purchase of shares															$ 25,000,000
Beckley Psytech Limited [Member] | Secondary Sale [Member]
Cash and Cash Equivalents [Line Items]
Investment measured at fair value as per fair value option							$ 32,400,000		$ 32,400,000
Beckley Psytech Limited [Member] | Secondary Sale [Member] | Series C Shares [Member]
Cash and Cash Equivalents [Line Items]
Share price | (per share)												$ 0.8966	€ 0.0001
Investment owned number of shares | shares												11,153,246
Purchase price of investment												$ 10,000,000
Beckley Psytech Limited [Member] | Secondary Sale [Member] | Additional Warrants [Member]
Cash and Cash Equivalents [Line Items]
Other Investments held at fair value												$ 2,600,000

Investments - (Additional Infor

Investments - (Additional Information) (Details)				1 Months Ended				3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 05, 2024 USD ($) $ / shares shares	Aug. 30, 2023 USD ($) $ / shares shares	Nov. 30, 2020 USD ($)	May 31, 2024 USD ($)	Nov. 30, 2023 USD ($)	Feb. 28, 2021 USD ($)	Nov. 30, 2020 USD ($)	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Dec. 31, 2023 USD ($) shares	Jun. 30, 2024 shares	May 01, 2024 USD ($)	Mar. 31, 2024 $ / shares shares	Mar. 15, 2024 USD ($)	Jan. 18, 2024 USD ($) $ / shares shares	Jan. 18, 2024 € / shares	Jan. 03, 2024 USD ($) $ / shares	Aug. 31, 2023 shares	Jun. 30, 2023 shares	Mar. 31, 2023 shares	Dec. 31, 2022 shares	Nov. 30, 2022 € / shares	Dec. 31, 2021 USD ($)	May 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Cash and Cash Equivalents [Line Items]
Proceeds from Issuance of Secured Debt										$ 2,400,000		$ 2,400,000
Equity Method Investments								$ 0		0		0													$ 0
Other Investments held at fair value								$ 45,227,000		$ 45,227,000		$ 89,825,000
Equity method investment, Shares transaction date										Dec. 31, 2026
Company received warrants to be purchase | shares								167,818,316		167,818,316		166,026,396
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure, Total												$ 100,000
Fair Value, Option, Changes in Fair Value, Gain (Loss)								$ 900,000	$ 1,800,000	$ 3,200,000	$ 3,300,000
Deferred purchase credit												$ 5,100,000
Equity method investment, Investee shares sold										9,600,000
Two Thousand Twenty Three Subsequent Notes [Member]
Cash and Cash Equivalents [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)								200,000		200,000
2024 Term Loan Warrants [Member]
Cash and Cash Equivalents [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)								$ 0		$ 400,000
Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Sale of stock issue price per share | € / shares																								€ 0.1
Shares, Outstanding | shares								167,818,316	166,010,476	167,818,316	166,010,476	166,026,396	167,771,990		166,274,426						166,010,476	166,010,476	165,935,914
Warrant [Member]
Cash and Cash Equivalents [Line Items]
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure, Total								$ 0		$ 0		$ 700,000
Fair Value, Option, Changes in Fair Value, Gain (Loss)								700,000		700,000
Warrant [Member] | 2024 Term Loan Warrants [Member]
Cash and Cash Equivalents [Line Items]
Warrants at fair value				$ 400,000						0
Company received warrants to be purchase | shares															4,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares															$ 0.17
Beckley Psytech Limited [Member]
Cash and Cash Equivalents [Line Items]
Deferred Payment shares | shares	9,036,144
Beckley Psytech Limited [Member] | Deferred Shares [Member]
Cash and Cash Equivalents [Line Items]
Deposited to an escrow account														$ 15,000,000
Draw down amount from escrow account	$ 5,000,000							5,000,000		5,000,000
Long term restricted cash for other investments								10,000,000		10,000,000
Sale of stock issue price per share | $ / shares	$ 1.66
Beckley Psytech Limited [Member] | Additional Warrants [Member]
Cash and Cash Equivalents [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																			$ 1.66
Beckley Psytech Limited [Member] | Series C Warrants [Member]
Cash and Cash Equivalents [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																			$ 2.158
GABA Therapeutics Inc [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investments								$ 0		$ 0																	$ 0
GABA Therapeutics Inc [Member] | Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, ownership percentage								7.20%		7.20%		3.60%
GABA Therapeutics Inc [Member] | Additional Shares [Member]
Cash and Cash Equivalents [Line Items]
Payments to acquire investments			$ 2,000
Innoplexus SPA [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, Investee shares sold						$ 2,400,000
Innoplexus AG [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, ownership percentage																											35%
Innoplexus AG [Member] | Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, ownership percentage								35%		35%		35%
Share Purchase Deed [Member] | Beckley Psytech Limited [Member] | Series C Preferred Shares [Member]
Cash and Cash Equivalents [Line Items]
Equity Method Investment, Aggregate Cost																			$ 10,000,000
Investment Owned, Balance, Shares | shares								11,153,246		11,153,246
Call Option [Member]
Cash and Cash Equivalents [Line Items]
Stock Issued During Period, Shares, Conversion of Units | shares										7,401
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure, Total								$ 5,200,000		$ 5,200,000		$ 5,100,000
Fair Value, Option, Changes in Fair Value, Gain (Loss)								$ 5,200,000		$ 5,200,000
Call Option [Member] | Convertible Notes Receivable [Member]
Cash and Cash Equivalents [Line Items]
Debt Instrument, Convertible, Conversion Price | $ / shares								$ 1,000		$ 1,000
Call Option [Member] | Common Stock [Member] | 2021 Purchase Right [Member]
Cash and Cash Equivalents [Line Items]
Shares, Outstanding | shares								100,000,000		100,000,000
Investment Owned, Balance, Shares | shares								100,000,000		100,000,000
Call Option [Member] | Common Stock [Member] | Maximum [Member] | 2021 Purchase Right [Member]
Cash and Cash Equivalents [Line Items]
Shares, Outstanding | shares								130,000,000		130,000,000
Call Option [Member] | Common Stock [Member] | Minimum [Member]
Cash and Cash Equivalents [Line Items]
Shares, Outstanding | shares								100,000,000		100,000,000
Call Option [Member] | Common Stock [Member] | Minimum [Member] | 2021 Purchase Right [Member]
Cash and Cash Equivalents [Line Items]
Shares, Outstanding | shares								100,000,000		100,000,000
Call Option [Member] | Warrant [Member]
Cash and Cash Equivalents [Line Items]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares								5,405		5,405
Omnibus Amendment Agreement [Member] | GABA Therapeutics Inc [Member]
Cash and Cash Equivalents [Line Items]
Payments to acquire investments							$ 1,800,000
Secondary Sale [Member] | Beckley Psytech Limited [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								$ 32,400,000		$ 32,400,000
Secondary Sale [Member] | Beckley Psytech Limited [Member] | Additional Warrants [Member]
Cash and Cash Equivalents [Line Items]
Other Investments held at fair value																	$ 2,600,000
Secondary Sale [Member] | Beckley Psytech Limited [Member] | Series C Shares [Member]
Cash and Cash Equivalents [Line Items]
Sale of stock issue price per share | (per share)																	$ 0.8966	€ 0.0001
Equity Method Investment, Aggregate Cost																	$ 10,000,000
Investment Owned, Balance, Shares | shares																	11,153,246
IntelGenx [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option					$ 800,000																					$ 12,300,000
Fair Value, Option, Changes in Fair Value, Gain (Loss)								0	$ 0	0	$ 0
IntelGenx [Member] | Convertible debenture [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option					600,000
IntelGenx [Member] | Convertible debenture [Member] | Two Thousand Twenty Three Subsequent Notes [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option					600,000
IntelGenx [Member] | Common Stock [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								3,000,000		3,000,000
IntelGenx [Member] | Warrant [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								1,200,000		1,200,000						$ 0
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure, Total								0		0		$ 200,000
IntelGenx [Member] | Warrant [Member] | Convertible debenture [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option					200,000
IntelGenx [Member] | Warrant [Member] | Convertible debenture [Member] | Two Thousand Twenty Three Subsequent Warrants [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option					200,000
IntelGenx [Member] | Unit [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								8,200,000		$ 8,200,000
IntelGenx [Member] | Subscription Agreement [Member] | Two Thousand Twenty Three Warrant [Member]
Cash and Cash Equivalents [Line Items]
Equity method investment, Shares transaction date										Aug. 31, 2026
IntelGenx [Member] | Subscription Agreement [Member] | Convertible Notes Receivable [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								$ 1,000,000		$ 1,000,000
Investment Interest Rate								12%		12%
Debt Instrument, Convertible, Conversion Price | $ / shares								$ 0.185		$ 0.185
IntelGenx [Member] | Subscription Agreement [Member] | Convertible debenture [Member]
Cash and Cash Equivalents [Line Items]
Proceeds from Issuance of Secured Debt		$ 2,200,000
Stock Issued During Period, Shares, Conversion of Units | shares		2,220
Debt Instrument, Convertible, Conversion Price | $ / shares		$ 1,000
Stock Issued During Period, Value, Conversion of Units		$ 750,000,000
IntelGenx [Member] | Subscription Agreement [Member] | Warrant [Member]
Cash and Cash Equivalents [Line Items]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares																				5,405
IntelGenx [Member] | Subscription Agreement [Member] | Warrant [Member] | Two Thousand Twenty Three Warrant [Member]
Cash and Cash Equivalents [Line Items]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares								5,405		5,405
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares								$ 0.26		$ 0.26
IntelGenx [Member] | Subscription Agreement [Member] | Unit [Member] | Convertible debenture [Member]
Cash and Cash Equivalents [Line Items]
Stock Issued During Period, Shares, Conversion of Units | shares		750
Stock Issued During Period, Value, Conversion of Units					$ 750,000,000
IntelGenx [Member] | Call Option [Member] | Convertible Notes Receivable [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								$ 1,500,000		$ 1,500,000
IntelGenx [Member] | Call Option [Member] | Convertible debenture [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								2,200,000		2,200,000
IntelGenx [Member] | Call Option [Member] | Warrant [Member] | Convertible debenture [Member] | Two Thousand Twenty Three Warrant [Member]
Cash and Cash Equivalents [Line Items]
Investment Measured At Fair Value Using Fair Value Option								700,000		700,000
IntelGenx [Member] | Strategic Development Agreement [Member]
Cash and Cash Equivalents [Line Items]
Research & development expense								200,000	$ 100,000	600,000	$ 300,000
Credit received								$ 2,500,000		$ 2,500,000
Percentage of the funds to be used for research and development purpose								20%		20%

Notes Receivable - Additional I

Notes Receivable - Additional Information (Detail) $ / shares in Units, $ in Millions				3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2023 USD ($)	Aug. 30, 2023 USD ($) shares	Sep. 14, 2021 USD ($)	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) $ / shares	Sep. 30, 2024 € / shares	Sep. 30, 2024 CAD ($) shares	May 31, 2024 USD ($)	May 31, 2024 CAD ($)	Mar. 31, 2024 USD ($)	Mar. 15, 2024 USD ($)	Dec. 31, 2023 € / shares	Aug. 31, 2023	Jan. 01, 2023 USD ($)	May 31, 2021 USD ($)	Mar. 08, 2021 USD ($)
Notes Receivable [Line Items]
Secured debt						$ 2,400,000		$ 2,400,000
Equity method investment, Shares transaction date						Dec. 31, 2026
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure								100,000
Change in fair value of assets and liabilities, net				$ 900,000	$ 1,800,000	$ 3,200,000	$ 3,300,000
Other current liabilities				147,000		147,000		0
Convertible notes receivable - related party				0		0		11,202,000
Other Investments held at fair value				45,227,000		45,227,000		$ 89,825,000
Short-term debt securities				$ 56,000,000		$ 56,000,000
Issuance of common stock shares par value | (per share)				$ 0.11		$ 0.11		$ 0.12	€ 0.1						€ 0.1
Additional Term Loan Receivable [Member] | First Tranche [Member]
Notes Receivable [Line Items]
Convertible notes receivable - related party				$ 1,000,000		$ 1,000,000
Additional Term Loan Receivable [Member] | Second Tranche [Member]
Notes Receivable [Line Items]
Convertible notes receivable - related party				1,000,000		$ 1,000,000
Term Loan Receivable [Member]
Notes Receivable [Line Items]
Accumulated Deficit Net Of Tax																	$ 400,000
Loans Receivable [Member]
Notes Receivable [Line Items]
Receivables, Maturity description						In September 2021, the Company entered into an amended and restated loan agreement which, among other things, increased the principal amount of loans available to IntelGenx by $6.0 million, for a total of up to $8.5 million, collectively the “Initial Tranches”. The additional $6.0 million loan amount was funded via two separate $3.0 million tranches in January 2022 and January 2023.
Warrant [Member]
Notes Receivable [Line Items]
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure				0		$ 0		$ 700,000
Change in fair value of assets and liabilities, net				700,000		700,000
Debtor-in-Possession Loan
Notes Receivable [Line Items]
Change in fair value of assets and liabilities, net				$ 500,000		$ 500,000
Loan Annualized Rate Of Interest				6.45%		6.45%				6.45%
Debtor-in-Possession Loan | Maximum [Member]
Notes Receivable [Line Items]
Line of credit											$ 5,900,000	$ 8
Subsequent DIP Loan Commitment
Notes Receivable [Line Items]
Other current liabilities				$ 100,000		$ 100,000
IntelGenx Corp [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				2,200,000		$ 2,200,000
IntelGenx Corp [Member] | March Term Loan Receivable [Member]
Notes Receivable [Line Items]
Receivable, Face amount																			$ 2,000,000
Loans receivable, Fixed interest rate						8%
IntelGenx Corp [Member] | Additional Term Loan Receivable [Member]
Notes Receivable [Line Items]
Receivable, Face amount																			$ 500,000
IntelGenx Corp [Member] | Additional Term Loan Receivable [Member] | Amended and Restated Loan Agreement [Member]
Notes Receivable [Line Items]
Receivable, Face amount			$ 3,000,000
IntelGenx Corp [Member] | Additional Term Loan Receivable [Member] | First Tranche [Member]
Notes Receivable [Line Items]
Receivable, Face amount													$ 1,000,000
IntelGenx Corp [Member] | Additional Term Loan Receivable [Member] | Second Tranche [Member]
Notes Receivable [Line Items]
Receivable, Face amount													$ 1,000,000
IntelGenx Corp [Member] | Term Loan Receivable [Member]
Notes Receivable [Line Items]
Change in fair value of assets and liabilities, net				7,000,000		$ 11,100,000
Receivable, Face amount			8,500,000
Conversion Price					0.185		0.185
Notes receivable, fair value disclosure	$ 9,200,000
Long-Term Debt, Fair Value								8,600,000
Interest income				0	200,000	0	500,000
IntelGenx Corp [Member] | Term Loan Receivable [Member] | Amended and Restated Loan Agreement [Member]
Notes Receivable [Line Items]
Receivable, Face amount			6,000,000
Loan agreement			$ 6,000,000
IntelGenx Corp [Member] | Term Loan Receivable [Member] | First Tranche [Member]
Notes Receivable [Line Items]
Conversion Price				0.185		0.185
IntelGenx Corp [Member] | Term Loan Receivable [Member] | Minimum [Member] | Amended and Restated Loan Agreement [Member]
Notes Receivable [Line Items]
Term loan maturity date																Jan. 05, 2024
IntelGenx Corp [Member] | Term Loan Receivable [Member] | Maximum [Member] | Amended and Restated Loan Agreement [Member]
Notes Receivable [Line Items]
Term loan maturity date																Jan. 05, 2025
IntelGenx Corp [Member] | Two Thousand Twenty Three Term Loan Note [Member]
Notes Receivable [Line Items]
Receivable, Face amount								500,000
Long-Term Debt, Fair Value				0		0		$ 500,000
Loans receivable, Fixed interest rate								14%
IntelGenx Corp [Member] | Common Stock [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				1,500,000		1,500,000
IntelGenx Corp [Member] | Warrant [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				$ 700,000		$ 700,000
IntelGenx Corp [Member] | Warrant [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Common share purchase warrants | shares				5,405		5,405				5,405
IntelGenx Corp [Member] | 2024 Warrants [Member]
Notes Receivable [Line Items]
Other Investments held at fair value				$ 400,000		$ 400,000
IntelGenx Corp [Member] | 2024 Warrants [Member] | Additional Term Loan Receivable [Member]
Notes Receivable [Line Items]
Issuance of common shares						$ 4,000,000
Warrant exercise price | $ / shares						$ 0.17
IntelGenx Corp [Member] | Convertible Notes Receivable [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				1,000		$ 1,000
IntelGenx Corp [Member] | Convertible Notes Receivable [Member] | Unit [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				$ 1,000		$ 1,000
IntelGenx Corp [Member] | Convertible debenture [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Secured debt		$ 2,200,000
Convertible debenture units | shares		2,220
Common share purchase warrants | shares				5,405		5,405				5,405
IntelGenx Corp [Member] | Convertible debenture [Member] | Unit [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Convertible debenture units | shares						750
IntelGenx [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option	800,000																	$ 12,300,000
Change in fair value of assets and liabilities, net				$ 0	0	$ 0	0
IntelGenx [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure								$ 500,000
IntelGenx [Member] | Common Stock [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				3,000,000		3,000,000
IntelGenx [Member] | Warrant [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				1,200,000		1,200,000								$ 0
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure				$ 0		$ 0		200,000
IntelGenx [Member] | Warrant [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Exercise price, warrants | $ / shares				$ 0.26		$ 0.26
IntelGenx [Member] | Unit [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option				$ 8,200,000		$ 8,200,000
IntelGenx [Member] | 2023 Warrant [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Equity method investment, Shares transaction date						Aug. 31, 2026
IntelGenx [Member] | Convertible Notes Receivable [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Interes rate				12%		12%				12%
Debt conversion price | $ / shares				$ 0.185		$ 0.185
IntelGenx [Member] | Convertible debenture [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option	600,000
IntelGenx [Member] | Convertible debenture [Member] | Warrant [Member]
Notes Receivable [Line Items]
Investment measured at fair value as per fair value option	200,000
IntelGenx [Member] | Convertible debenture [Member] | Unit [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Conversion of units, debentures, Value	$ 750,000					$ 750,000
IntelGenx [Member] | 2023 Initial Notes [Member]
Notes Receivable [Line Items]
Change in fair value of assets and liabilities, net				$ 900,000	$ 100,000	1,800,000	$ 100,000
IntelGenx [Member] | 2023 Initial Notes [Member] | Subscription Agreement [Member]
Notes Receivable [Line Items]
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure								$ 1,800,000
IntelGenx [Member] | 2023 Term Loan Note [Member]
Notes Receivable [Line Items]
Change in fair value of assets and liabilities, net				200,000		500,000
IntelGenx [Member] | Debtor-in-Possession Loan
Notes Receivable [Line Items]
Change in fair value of assets and liabilities, net				200,000
Receivable, Face amount				100,000		100,000				$ 0.2
Long-Term Debt, Fair Value				5,700,000		5,700,000				$ 7.8
Short-term debt securities				5,700,000		5,700,000
IntelGenx [Member] | 2023 Subsequent Notes [Member]
Notes Receivable [Line Items]
Change in fair value of assets and liabilities, net				$ 300,000		$ 500,000

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Fair Value Measurement on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Liabilities:
Other current liabilities	$ 147	$ 0
Contingent consideration liability	1,388	1,637
Fair Value, Recurring [Member]
Cash equivalents:
Other investment at fair value	45,227	89,825
Assets fair value	107,713	210,306
Liabilities:
Other current liabilities	147
Contingent consideration liability—related parties	650	620
Contingent consideration liability	1,388	1,637
2018 convertible promissory note conversion option	1,239	2,385
Liability fair value	2,796	4,643
Fair Value, Recurring [Member] | U.S. Treasuries [Member]
Cash equivalents:
Fair value of debt securities	51,358	67,119
Fair Value, Recurring [Member] | Money Market Funds [Member]
Cash equivalents:
Cash and cash equivalents, fair value	829	56
Fair Value, Recurring [Member] | Corporate Notes/Bonds [Member]
Cash equivalents:
Fair value of debt securities		5,007
Fair Value, Recurring [Member] | Convertible Notes Receivable - Related Party [Member]
Cash equivalents:
Other investment at fair value		11,202
Fair Value, Recurring [Member] | U.S. Government Agencies [Member]
Cash equivalents:
Fair value of debt securities	4,599	37,097
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents:
Other investment at fair value	43,506	83,701
Assets fair value	44,335	83,757
Liabilities:
Other current liabilities	0
Contingent consideration liability—related parties	0	0
Contingent consideration liability	0	0
2018 convertible promissory note conversion option	0	0
Liability fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Treasuries [Member]
Cash equivalents:
Fair value of debt securities	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Cash equivalents:
Cash and cash equivalents, fair value	829	56
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Notes/Bonds [Member]
Cash equivalents:
Fair value of debt securities		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Convertible Notes Receivable - Related Party [Member]
Cash equivalents:
Other investment at fair value		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government Agencies [Member]
Cash equivalents:
Fair value of debt securities	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents:
Other investment at fair value	0	0
Assets fair value	55,957	109,223
Liabilities:
Other current liabilities	0
Contingent consideration liability—related parties	0	0
Contingent consideration liability	0	0
2018 convertible promissory note conversion option	0	0
Liability fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Treasuries [Member]
Cash equivalents:
Fair value of debt securities	51,358	67,119
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Cash equivalents:
Cash and cash equivalents, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Notes/Bonds [Member]
Cash equivalents:
Fair value of debt securities		5,007
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Convertible Notes Receivable - Related Party [Member]
Cash equivalents:
Other investment at fair value		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government Agencies [Member]
Cash equivalents:
Fair value of debt securities	4,599	37,097
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents:
Other investment at fair value	1,721	6,124
Assets fair value	7,421	17,326
Liabilities:
Other current liabilities	147
Contingent consideration liability—related parties	650	620
Contingent consideration liability	1,388	1,637
2018 convertible promissory note conversion option	1,239	2,385
Liability fair value	2,796	4,643
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Treasuries [Member]
Cash equivalents:
Fair value of debt securities	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Cash equivalents:
Cash and cash equivalents, fair value	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Notes/Bonds [Member]
Cash equivalents:
Fair value of debt securities		0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Convertible Notes Receivable - Related Party [Member]
Cash equivalents:
Other investment at fair value		11,202
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government Agencies [Member]
Cash equivalents:
Fair value of debt securities	0	$ 0
Fair Value, Recurring [Member] | Related Party [Member]
Liabilities:
2018 convertible promissory note conversion option	758
Fair Value, Recurring [Member] | Related Party [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities:
2018 convertible promissory note conversion option	0
Fair Value, Recurring [Member] | Related Party [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities:
2018 convertible promissory note conversion option	0
Fair Value, Recurring [Member] | Related Party [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities:
2018 convertible promissory note conversion option	758
Fair Value, Recurring [Member] | Notes Receivable [Member]
Cash equivalents:
Other investment at fair value	5,700
Fair Value, Recurring [Member] | Notes Receivable [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents:
Other investment at fair value	0
Fair Value, Recurring [Member] | Notes Receivable [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents:
Other investment at fair value	0
Fair Value, Recurring [Member] | Notes Receivable [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents:
Other investment at fair value	$ 5,700

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Fair Value Measurement Inputs and Valuation Techniques (Detail) - Contingent Consideration Liability Related Parties [Member]	Sep. 30, 2024	Dec. 31, 2023
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.113	0.135
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | DemeRx [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration		0.139
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | DemeRx [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.113
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | DemeRx [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.114
Measurement Input Probability of the Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.28	0.28
Measurement Input Probability of the Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | DemeRx [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.20	0.20
Measurement Input Probability of the Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | DemeRx [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.25	0.25
Measurement Input Discount Rate for Royalties [Member] | Discounted Cash Flow With Scenario Based Method [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.11	0.13
Measurement Input Discount Rate for Royalties [Member] | Discounted Cash Flow With Scenario Based Method [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.127	0.142
Measurement Input Discount Rate for Royalties on Milestones [Member] | Discounted Cash Flow With Scenario Based Method [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.11	0.13
Measurement Input Discount Rate for Royalties on Milestones [Member] | Discounted Cash Flow With Scenario Based Method [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.127	0.142
Probability of Success Rate [Member] | Discounted Cash Flow With Scenario Based Method [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration	0.28
Probability of Success Rate [Member] | Discounted Cash Flow With Scenario Based Method [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration		0.134
Probability of Success Rate [Member] | Discounted Cash Flow With Scenario Based Method [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration		0.28

Fair Value Measurement - Summ_3

Fair Value Measurement - Summary of Fair Value Measurement on Recurring Basis, Unobservable Input Reconciliation (Detail) - USD ($) $ in Thousands		3 Months Ended
		Sep. 30, 2024		Jun. 30, 2024		Mar. 31, 2024		Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023
Convertible Notes Receivable - Related Party [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance										$ 0
Beginning Balance		$ 9,872	[1]	$ 13,902	[1]	$ 11,202	[1]	$ 0	$ 0
Initial fair value of instrument		3,830	[1]	3,425	[1]	988	[1]	1,497		0
Additional Warrants received	[1]	0
Change in fair value, including interest		(8,002)	[1]	(7,455)	[1]	1,712	[1]	22	0	0
Extinguishment of liability								0	0	0
Ending Balance		5,700	[1]	9,872	[1]	13,902	[1]	1,519	0	0
IntelGenx Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[2]	0		7,973		6,124
Initial fair value of instrument	[2]	0		0		420
Additional Warrants received	[2]	0
Change in fair value, including interest	[2]	0		(7,973)		1,429
Ending Balance	[2]	0		0		7,973
IntelGenx 2023 Initial Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[1]									0
Beginning Balance	[1]							0	0
Initial fair value of instrument	[1]							724		0
Change in fair value, including interest	[1]							0	0	0
Extinguishment of liability	[1]							0	0	0
Ending Balance	[1]							724	0	0
IntelGenx subsequent DIP Loan commitment [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		680		0		0
Initial fair value of instrument		0		680		0
Additional Warrants received		0
Change in fair value, including interest		(533)		0		0
Ending Balance		147		680		0
Contingent Consideration Liability Related Parties [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance										953
Beginning Balance		580	[3]	607	[3]	620	[3]	842	918
Initial fair value of instrument		0	[3]	0	[3]	0	[3]	0	0	0
Additional Warrants received	[3]	0
Change in fair value, including interest		70	[3]	(27)	[3]	(13)	[3]	58	(76)	(35)
Extinguishment of liability								0	0	0
Ending Balance		650	[3]	580	[3]	607	[3]	$ 900	$ 842	$ 918
Contingent Consideration Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	[4]	1,373		1,406		1,637
Initial fair value of instrument	[4]	0		0		0
Additional Warrants received	[4]	0
Change in fair value, including interest	[4]	15		(32)		(231)
Ending Balance	[4]	1,388		1,373		1,406
2018 Convertible Notes Call Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		2,929		4,119		2,385
Initial fair value of instrument		0		3,590		0
Additional Warrants received		0
Change in fair value, including interest		(932)		(4,780)		1,734
Ending Balance		1,997		2,929		4,119
Beckley Additional Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance		3,364		2,645		0
Initial fair value of instrument		0		0		2,645
Additional Warrants received		(1,538)
Change in fair value, including interest		(105)		720		0
Ending Balance		$ 1,721		$ 3,364		$ 2,645
[1] Includes the IntelGenx Term Loan, the 2023 Initial Notes, the 2023 Subsequent Notes, the DIP Loan, and the 2023 Term Loan Note. Includes the 2023 Initial Warrants, the 2023 Subsequent Warrants, the 2024 Warrants, and the Call Option Units. Includes Perception milestone based contingent consideration liability. Includes contingent consideration liability related to DemeRx IB Stock Purchase and contingent consideration liability related to the TryptageniX research and development milestone success fee payments and royalties payments.

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 31, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2024 CAD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short term notes receivable - related party, net		$ 5,700,000		$ 5,700,000		$ 505,000
Volatility				75%		78.60%
Change in fair value of assets and liabilities, net		900,000	$ 1,800,000	$ 3,200,000	$ 3,300,000
DIP Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loan commitment		100,000		100,000			$ 0.2
Short term notes receivable - related party, net		5,700,000		5,700,000
IntelGenx Term Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unsecured Debt		0		0
2023 Initial Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unsecured Debt		0		0
2023 Subsequent Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unsecured Debt		0		0
ATAI LIFE SCIENCES N.V. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) from change in fair value of the derivative liability		1,000,000		3,900,000
Warrant [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of assets and liabilities, net		700,000		700,000
Compass Pathways Plc [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of assets and liabilities, net		3,900,000	$ 69,000,000	22,000,000	$ 69,000,000
DemeRx [Member] | Stock Purchase And Framework Agreement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business combination, earn-out consideration	$ 8,000,000
Fair value of the contingent milestone and royalty liabilities		$ 1,200,000		$ 1,200,000		$ 1,400,000
IntelGenx [Member] | DIP Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate		12.50%		12.50%			12.50%
IntelGenx [Member] | 2023 Initial Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		$ 0		$ 0		700,000
IntelGenx [Member] | 2023 Subsequent Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		0		0		$ 200,000
IntelGenx [Member] | 2024 Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value		0		0
IntelGenx [Member] | Call Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate						45.90%
Fair value		0		0		$ 5,200,000
TryptageniX Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of the contingent milestone and royalty liabilities		$ 200,000		$ 200,000		$ 200,000
Additional Warrants [Member] | Beckley Psytech Limited [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant Liability, Measurement Input Including Discount for Lack of Marketability		0.90		0.90			0.90
Fair value		$ 1,700,000		$ 1,700,000
Additional Warrants [Member] | Beckley Psytech Limited [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of Issuances under Deferred Equity Arrangement		50%		50%			50%
Additional Warrants [Member] | Beckley Psytech Limited [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of Issuances under Deferred Equity Arrangement		80%		80%			80%
Fair Value, Inputs, Level 3 [Member] | Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of common stock by applying discount for lack of marketability						5%
Fair Value, Inputs, Level 3 [Member] | Call Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of common stock by applying discount for lack of marketability						5%
Royalty Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of the contingent milestone and royalty liabilities		$ 700,000		$ 700,000		$ 600,000
Value Of Underlying [Member] | Fair Value, Inputs, Level 3 [Member] | IntelGenx [Member] | Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative Investment, Measurement Input Including Discount for Lack of Marketability						0.13
Value Of Underlying [Member] | Fair Value, Inputs, Level 3 [Member] | IntelGenx [Member] | Call Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative Investment, Measurement Input Including Discount for Lack of Marketability						0.13
Measurement Input, Price Volatility [Member] | Fair Value, Inputs, Level 3 [Member] | Warrants [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant Liability, Measurement Input Including Discount for Lack of Marketability						1
Measurement Input, Price Volatility [Member] | Fair Value, Inputs, Level 3 [Member] | Call Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant Liability, Measurement Input Including Discount for Lack of Marketability						1

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid research and development related expenses	$ 4,208	$ 1,822
Tax receivables	1,253	1,752
Prepaid insurance	1,074	1,410
Other	919	846
Total	$ 7,454	$ 5,830

Accrued Liabilities - Summary o

Accrued Liabilities - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Accrued accounting, legal, and other professional fees	$ 4,540	$ 5,468
Accrued external research and development expenses	3,657	3,031
Accrued payroll	2,350	4,941
Other liabilities	1,114	1,101
Taxes payable	182	715
Accrued restructuring costs	110	0
Total	$ 11,953	$ 15,256

Leases (Additional Information)

Leases (Additional Information) (Details)	Sep. 30, 2024
Leases [Abstract]
Operating Lease, Weighted Average Discount Rate, Percent	12.80%
Operating Lease, Weighted Average Remaining Lease Term	3 years 7 months 6 days

Leases - Schedule of operating

Leases - Schedule of operating leases assets and liabilities lessee (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Leases [Abstract]
Operating lease right-of-use asset, net	$ 1,032	$ 1,223
Current portion of lease liability	$ 257	$ 275
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Operating lease right-of-use asset, net	Operating lease right-of-use asset, net
Noncurrent portion of lease liability	$ 808	$ 990
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Noncurrent portion of lease liability	Noncurrent portion of lease liability

Leases - Components of expenses

Leases - Components of expenses related to leases is recorded on a straight-line basis over the lease term (Details) - General and Administrative Expense [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating lease cost	$ 87	$ 120	$ 317	$ 431
Short-term lease cost	33	102	110	384
Total lease cost	$ 120	$ 222	$ 427	$ 815

Leases - Schedule of future min

Leases - Schedule of future minimum commitments maturity operating leases (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Leases [Abstract]
2024 (excluding nine months ended September 30, 2024)	$ 94
2025	375
2026	375
2027	375
2028	125
Total lease payments	1,344
Less: Imputed interest	(279)
Present value of lease liabilities	$ 1,065

Leases - Schedule of supplement

Leases - Schedule of supplemental cash flow information related to operating leases (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 326	$ 304
Right of use asset obtained in exchange for operating lease liabilities	$ 0	$ 1,356

Debt - Additional Information (

Debt - Additional Information (Detail) € / shares in Units, $ / shares in Units, € in Thousands, $ in Thousands		1 Months Ended			3 Months Ended		9 Months Ended
	Aug. 14, 2024 USD ($)	Apr. 30, 2024 CommonStock $ / shares	Nov. 30, 2023 CommonStock $ / shares	Aug. 31, 2022 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Apr. 30, 2024 EUR (€)	Dec. 31, 2023 USD ($)	Nov. 30, 2023 EUR (€)	Aug. 31, 2023 USD ($)	May 26, 2023 USD ($)	Oct. 31, 2020 € / shares	Oct. 31, 2018 USD ($)	Oct. 31, 2018 EUR (€)
Debt Instrument [Line Items]
Convertible promissory notes issued					$ 20,000		$ 20,000			$ 15,000
Fair value of the outstanding debt obligation					$ 20,336		$ 20,336			15,047
Maturity date					Aug. 01, 2026		Aug. 01, 2026
Debt Instrument, Convertible, Number of Equity Instruments | CommonStock		16	16
Prime rate percent	4.30%				4.30%		4.30%
Cash proceeds from certain permitted sources							$ 175,000
Accrued interest payable, percent	9.05%				9.05%		9.05%
Gain (loss) from change in fair value of the derivative liability					$ 1,000		$ 3,900
Borrowing amount percentage	70%			70%
Principal amount				$ 175,000
Maximum [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued															$ 1,200	€ 1,000
ATAI LIFE SCIENCES N.V. [Member]
Debt Instrument [Line Items]
Debt conversion price | (per share)		$ 17	$ 17											€ 17
Face value of convertible notes | €									€ 1		€ 1
2020 Convertible Note Agreement [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued					1,500		1,500			2,700
2020 Convertible Note Agreement [Member] | ATAI LIFE SCIENCES N.V. [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued					900		900
2018 Convertible Note Agreement [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued										1,500
Carrying amount of convertible promissory note										200
Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Fair value of the outstanding debt obligation					$ 20,400		$ 20,400			$ 16,200
Prime rate percent	4.05%				4.05%		4.05%
Interest expense					$ 100	$ 100	$ 300	$ 300
Line of credit													$ 30,000
Borrowing amount percentage	50%			50%
Market capitalization daily basis	$ 550,000											$ 550,000	550,000
Loan agreement description							In addition, the financial covenant under the 2022 Term Loan Agreement requires that beginning on October 1, 2024, the Company shall maintain Qualified Cash in an amount no less than the sum of (1) 50% of the outstanding amount under the 2022 Term Loan Facility, and (2) the amount of the Borrowers’ and Subsidiary Guarantors’ accounts payable that have not been paid within 180 days from the invoice date of the relevant account payable, subject to certain exceptions; provided, upon the occurrence of certain conditions, the Company shall at all times maintain Qualified cash in an amount no less than the sum of (1) 70% of the outstanding amount under the 2022 Term Loan Facility, and (2) the amount of the Borrowers’ and Subsidiary Guarantors’ accounts payable that have not been paid within 180 days from the invoice date of the relevant account payable, subject to certain exceptions; provided, further, that the financial covenant shall not apply on any day that the Company's market capitalization is at least $550.0 million measured on a consecutive 10-business day period immediately prior to such date of measurement and tested on a daily basis.
Term charge percentage				6.95%
Hercules Loan Agreement [Member] | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Line of credit													40,000
Hercules Loan Agreement [Member] | Tranche 1 | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Term loan advance	25,000
Hercules Loan Agreement [Member] | Tranche 1B | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Term loan advance	5,000												10,000
Hercules Loan Agreement [Member] | Tranche 1C | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Term loan advance													15,000
Hercules Loan Agreement [Member] | Tranche 1D | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Term loan advance													20,000
Hercules Loan Agreement [Member] | Tranche 2 | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Term loan advance	30,000												$ 15,000
Hercules Loan Agreement [Member] | Tranche 3 | Line of Credit Agreements [Member]
Debt Instrument [Line Items]
Term loan advance	$ 100,000
Prepayment occurs on or prior to the first anniversary[Member] | Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment principal amount percentage				2%
Prepayment occurs after the first anniversary and on or prior to the second anniversary [Member] | Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment principal amount percentage				1%
Prepayment occurs after the second anniversary [Member] | Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment principal amount percentage				0.50%

Debt - Summary of Grant Date Fa

Debt - Summary of Grant Date Fair Value (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Volatility	75%	78.60%

Debt - Schedule of Outstanding

Debt - Schedule of Outstanding debt obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt and Lease Obligation [Abstract]
Principal amount	$ 20,000	$ 15,000
End of the term charge	1,042	1,042
Less: unamortized issuance discount	(144)	(204)
Less: unamortized issuance costs	(60)	(84)
Less: unamortized end of term charge	(502)	(707)
Net carrying amount	20,336	15,047
Less: current maturities	0	0
Long-term debt, net of current maturities and unamortized debt discount and issuance costs	$ 20,336	$ 15,047

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - Common Stock [Member]	1 Months Ended	9 Months Ended
	Nov. 30, 2022 USD ($)	Sep. 30, 2024 USD ($)	Nov. 30, 2022 € / shares
Class of Stock [Line Items]
Sale of stock issue price per share | € / shares			€ 0.1
Proceeds from issuance of IPO | $	$ 150,000,000	$ 0

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Weighted average grant-date fair value of options granted			$ 1.19	$ 0.97
Other Subsidiaries Equity Plan
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized stock based compensation compensation, Expected period of recognition			10 months 20 days
Stock-Based Payment Arrangement, Expense	$ 100	$ 100	$ 100	$ 300
Restricted Stock [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized stock based compensation compensation	500		$ 500
Expected weighted average period			4 months 24 days
Fair Value Of Restricted Stock			$ 1,700
Stock-Based Payment Arrangement, Expense	$ 500	500	$ 1,300	1,000
HSOP Plan[Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares reserved for future issuance	257,419		257,419
Unrecognized stock based compensation compensation	$ 0		$ 0
Stock-Based Payment Arrangement, Expense	0	700	$ 100	2,500
HSOP Plan[Member] | HSOP Shares [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based payment arrangements, Equity instruments other than options granted			0
Two Thousand And Twenty Incentive Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based payment arrangements, Award vesting rights percentage			33%
Unrecognized stock based compensation compensation	23,600		$ 23,600
Unrecognized stock based compensation compensation, Expected period of recognition			2 years 10 days
Stock-Based Payment Arrangement, Expense	$ 4,600	$ 6,900	$ 15,500	$ 21,600
Number of options outstanding	0		0
Number of options outstanding, including both vested and non-vested options.	18,321,366		18,321,366
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			412,000
Two Thousand And Twenty One Incentive Award Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Shares reserved for future issuance	40,791,437		40,791,437

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of share based Payment Arrangement Option Activity (Detail) - Service And Performance Based Options [Member] - Two Thousand And Twenty Incentive Plan [Member] $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares		Dec. 31, 2023 USD ($) $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number Of Options Outstanding as of December 31, 2023 | shares	39,066,454
Number of Options, Granted | shares	10,783,294	[1]
Number of Options, Exercised | shares	(322,857)
Number of options, Cancelled or forfeited | shares	(7,589,498)
Number of options Outstanding as of September 30, 2024 | shares	41,937,393	[2]	39,066,454
Number of Options exercisable as of September 30, 2024 | shares	23,616,028
Weighted-Average Exercise Price as of December 31, 2023 | $ / shares	$ 4.62
Weighted-Average Exercise Price, Granted | $ / shares	1.75
Weighted-Average Exercise Price, Exercised | $ / shares	2.06
Weighted-Average Exercise Price, Cancelled or forfeited | $ / shares	5.35
Weighted-Average Exercise Price as of September 30, 2024 | $ / shares	3.78		$ 4.62
Weighted-Average Exercise Price Options exercisable as of September 30, 2024 | $ / shares	$ 4.69
Weighted-Average Remaining Contractual Term (Years)	5 years 9 months 25 days		5 years 6 months 21 days
Weighted-Average Remaining Contractual Term (Years), Options exercisable as of September 30, 2024	3 years 9 months 3 days
Aggregate Intrinsic Value, Outstanding | $	$ 3,367		$ 6,294
Aggregate Intrinsic Value, Options exercisable as of September 30, 2024 | $	$ 3,350
[1] Includes (a) 7,757,000 stock options with 25 % vesting on January 1, 2025 and the remaining over a three-year service period, (b) 1,016,094 stock options that will vest upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares, (c) 1,083,200 stock options that will vest over a four-year service period, (d) 515,000 stock options that will vest after a one-year service period, and (e) 412,000 stock options with 33 % vesting on the first anniversary of the grant date and the remaining over a two-year service period. The 18,321,366 outstanding unvested stock options includes (a) 9,199,618 stock options that will continue to vest over a one to four-year service period, (b) 7,013,000 options with 25 % vesting on January 1, 2025 and the remaining over a three-year service period, (c) 1,016,094 stock options that will vest upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares, (d) 992,654 that will continue to vest over a three to four-year service period and upon the satisfaction of specified performance-based vesting conditions, and (e) 100,000 stock options that will continue to vest over a two-year service period and upon the satisfaction of specified market-based conditions tied to the price of the Company's publicly traded shares.

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summery of Vested and Non vested Option Outstanding (Parenthetical) (Details) - Two Thousand And Twenty Incentive Plan [Member] - shares		9 Months Ended
	Jan. 01, 2025	Sep. 30, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options, Granted		412,000
Share based payment arrangements, Award vesting rights percentage		33%
Number of options outstanding, including both vested and non-vested options.		18,321,366
Market-Based Conditions [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options, Granted		1,016,094
Number of options outstanding, including both vested and non-vested options.		1,016,094
One to four year service period [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of options outstanding, including both vested and non-vested options.		9,199,618
Three To Four Year Service Period [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of options outstanding, including both vested and non-vested options.		992,654
Four Year Service Period [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options, Granted		1,083,200
Two Year Service Period [Member] | Market-Based Conditions [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share based payment arrangement, Options expected to vest outstanding		100,000
One Year Service Period [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options, Granted		515,000
Forecast [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Options, Granted	7,757,000
Share based payment arrangements, Award vesting rights percentage	25%
Number of options outstanding, including both vested and non-vested options.	7,013,000

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions (Detail)	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average expected stock price volatility	75%		78.60%
Service And Performance Based Options [Member] | Two Thousand And Twenty Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted average expected term in years	5 years 11 months 12 days	6 years 1 month 24 days
Weighted average expected stock price volatility	73.90%	87.50%
Risk-free interest rate, Minimum	3.78%	3.50%
Risk-free interest rate, Maximum	4.40%	4.09%
Expected dividend yield	0%	0%

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of restricted common stock awards activity (Detail) - Restricted Stock Units (RSUs) [Member]	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Share Based Arrangements To Obtain Goods And Services [Line Items]
Number of optionsOutstanding as of December 31, 2023 | shares	2,944,935
Number of Options, Granted | shares	0
Number of options,Vested | shares	1,469,063
Number of options,Forfeited | shares	348,815
Number of options Outstanding as of September 30, 2024 | shares	1,127,057
Weighted Average Grant Date Fair Value at December 31, 2023 | $ / shares	$ 1.18
Weighted Average Grant Date Fair Value, Granted | $ / shares	0
Weighted Average Grant Date Fair Value, Vested | $ / shares	1.18
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	1.18
Weighted Average Grant Date Fair Value at September 30, 2024 | $ / shares	$ 1.18

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Employee Stock Ownership Plan (ESOP) Disclosures (Detail) - HSOP Shares [Member] - HSOP Plan[Member] $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of optionsOutstanding as of December 31, 2023 | shares	6,921,829
Number of Options, Granted | shares	0
Number of options, Exercised | shares	0
Number of Options, Cancelled or forfeited | shares	0
Number of options Outstanding as of September 30, 2024 | shares	6,921,829	6,921,829
Number of Options,Options exercisable as of September 30, 2024 | shares	6,921,829
Weighted- Average Exercise Price Beginning as of December 31, 2023 | $ / shares	$ 6.64
Weighted- Average Exercise Price,Granted | $ / shares	0
Weighted-Average Exercise Price, Exercised | $ / shares	0
Weighted- Average Exercise Price, Cancelled or forfeited | $ / shares	0
Weighted- Average Exercise Price as of September 30, 2024 | $ / shares	6.64
Weighted- Average Exercise Price,Options exercisable as of June 30, 2024 | $ / shares	$ 6.64
Weighted- Average Remaining Contractual Term (Years)	11 years 4 months 2 days	12 years 3 days
Weighted- Average Remaining Contractual Term (Years),Options exercisable as of September 30, 2024	11 years 4 months 2 days
Aggregate Intrinsic Value,Beginning | $	$ 0

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of restricted stock awards (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	$ 5,046	$ 8,253	$ 17,088	$ 25,677
Atai ESOP [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	5,031	7,395	16,823	22,813
Atai HSOP [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	0	744	117	2,512
Other Subsidiaries Equity Plan
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	100	100	100	300
Other Subsidiaries Equity Plan | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	15	114	148	352
Research and Development Expense [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	1,964	3,392	6,452	10,186
Research and Development Expense [Member] | Atai ESOP [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	1,949	3,285	6,317	9,866
Research and Development Expense [Member] | Atai HSOP [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	0	0	0	0
Research and Development Expense [Member] | Other Subsidiaries Equity Plan | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	15	107	135	320
General and Administrative Expense [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	3,082	4,861	10,636	15,492
General and Administrative Expense [Member] | Atai ESOP [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	3,082	4,110	10,506	12,947
General and Administrative Expense [Member] | Atai HSOP [Member] | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	0	744	117	2,512
General and Administrative Expense [Member] | Other Subsidiaries Equity Plan | Options and Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-Based Payment Arrangement, Expense	$ 0	$ 7	$ 13	$ 33

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating Loss Carryforwards [Line Items]
Benefit from (provision for) income taxes	$ 178	$ (238)	$ 163	$ (588)

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net income (loss)	$ (26,311)	$ 43,371	$ (111,058)	$ (24,753)
Net loss attributable to noncontrolling interests	(25)	(873)	(747)	(2,821)
Net income (loss) attributable to ATAI Life Sciences N.V. shareholders - basic (numerator)	(26,286)	44,244	(110,311)	(21,932)
Net income (loss) attributable to ATAI Life Sciences N.V. shareholders - diluted (numerator)	$ (26,286)	$ 44,244	$ (110,311)	$ (21,932)
Diluted EPS
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. stockholders - basic	160,621,817	155,792,490	159,973,201	155,793,601
Net income (loss) per common share attributable to ATAI Life Sciences N.V. Shareholders - basic	$ (0.16)	$ 0.28	$ (0.69)	$ (0.14)
Net loss per share attributable to ATAI Life Sciences N.V. shareholders - diluted	$ (0.16)	$ 0.25	$ (0.69)	$ (0.14)
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. shareholders (denominator)	160,621,817	177,565,973	159,973,201	155,793,601
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			56,172,183	34,896,194
ATAI Life Sciences N.V. Shareholders [Member]
Diluted EPS
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. shareholders (denominator)	160,621,817	155,792,490	159,973,201	155,793,601
Options to purchase Common Stock
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			41,937,393	27,974,365
Options to purchase Common Stock | ATAI Life Sciences N.V. Shareholders [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	12,426,724	0	0
HSOP options to purchase common stock
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			6,921,829	6,921,829
Unvested Restricted Stock Units [Member] | ATAI Life Sciences N.V. Shareholders [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	3,144,935	0	0
2018 Convertible Promissory Notes - Related Parties
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			2,367,200	0
2018 Convertible Promissory Notes - Related Parties | ATAI Life Sciences N.V. Shareholders [Member]
Effect of dilutive securities:
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	6,201,824	0	0

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Computation of Diluted net Income (Loss) Per Share Attributable to Common Shareholders (Detail) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	56,172,183	34,896,194
Options to purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	41,937,393	27,974,365
HSOP options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	6,921,829	6,921,829
2018 Convertible Promissory Notes - Related Parties
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,367,200	0
2018 Convertible Promissory Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,818,704	0
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,127,057	0

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2023	Jan. 31, 2022	Jun. 30, 2020
License Agreements [Line Items]
Revenue Related To Certain Research And Development	$ 100	$ 100	$ 300	$ 300
Common Stock, Value, Issued	18,770		18,770				$ 18,573
ATAI Kures Inc. [Member] | License Agreement Terms [Member]
License Agreements [Line Items]
Percentage of the common stock shares outstanding									5%
Columbia Stock Purchase and License Agreement
License Agreements [Line Items]
Material Payment	0	0	0	0
Allergan License Agreement [Member]
License Agreements [Line Items]
Material Payment	0	0	0	0
Dalriada License Agreement [Member]
License Agreements [Line Items]
Service fees						$ 12,800
Dalriada License Agreement [Member] | Research And Development Services [Member]
License Agreements [Line Items]
process research And development expense	400	400	400	1,500	$ 600
Dalriada License Agreement [Member] | Service, Other [Member]
License Agreements [Line Items]
Service fees	0	$ 0	0	$ 0
Invyxis ESLA [Member]
License Agreements [Line Items]
Upfront deposit								$ 1,100
Invyxis ESLA [Member] | Minimum [Member]
License Agreements [Line Items]
Upfront deposit					500
Invyxis ESLA [Member] | Maximum [Member]
License Agreements [Line Items]
Upfront deposit					$ 1,100
Otsuka [Member] | Otsuka Agreement
License Agreements [Line Items]
Performance obligation						$ 20,000
Otsuka [Member] | Commercial Milestones [Member] | Otsuka Agreement
License Agreements [Line Items]
Milestone payments, receivable	66,000		66,000
Otsuka [Member] | Development And Regulatory Milestones [Member] | Otsuka Agreement
License Agreements [Line Items]
Milestone payments, receivable	$ 35,000		$ 35,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jan. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Percentage of common stock reserved				27%
General and administrative expense		$ 10,265	$ 13,631	$ 36,226	$ 44,159
General and Administrative Expense [Member]
Related Party Transaction [Line Items]
stock-based compensation		$ 100	200	$ 300	600
Founder [Member] | Atai Formation [Member]
Related Party Transaction [Line Items]
Equity method investment, ownership percentage		20.20%		20.20%			19.70%
Galaxy NYC Based Multi Strategy Investment Firm [Member] | Atai Formation [Member]
Related Party Transaction [Line Items]
Equity method investment, ownership percentage		6.40%		6.40%			6.50%
Apeiron [Member] | Common Stock [Member]
Related Party Transaction [Line Items]
Stock issued during period, Value				$ 10,500
Mr Angermayer [Member] | Consulting Agreement [Member]
Related Party Transaction [Line Items]
Grant of an option shares vested for continued service						1,658,094
General and administrative expense		$ 300	$ 100	$ 300	$ 400
Mr Angermayer [Member] | Consulting Agreement [Member] | Two Thousand And Twenty Incentive Plan [Member]
Related Party Transaction [Line Items]
Stock issued during period, share based payments	624,000

Defined Contribution Plan (Addi

Defined Contribution Plan (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Retirement Benefits [Abstract]
Labor and Related Expense	$ 0.1	$ 0.1	$ 0.3	$ 0.4

Corporate Restructuring (Additi

Corporate Restructuring (Additional Information) (Details) - USD ($) $ in Thousands			9 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Sep. 30, 2024	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Percentage of restructured workforce	10%	30%
Restructuring expense			$ 2,026	$ 3,206
Restructuring Reserve			110	0
Research and Development Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			300	1,800
General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			1,700	1,400
Deferred Compensation, Share-Based Payments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			400	200
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			$ 1,600	$ 3,000

Corporate Restructuring - Sched

Corporate Restructuring - Schedule Of Reconciliation Of The Cash Restructuring Charges And Related Payments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Restructuring costs expensed during the period	$ 2,026	$ 3,206
Non-cash impact of stock-based compensation	(358)	(195)
Cash payments of restructuring liabilities, net	(1,558)	(3,011)
Restructuring liability , Ending Balance	$ 110	$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Beckley Psytech Escrow Agreement [Member] - Subsequent Event [Member] shares in Millions, $ in Millions	1 Months Ended
	Oct. 31, 2024 USD ($) shares
Drewings from escrow account | $	$ 5
Series C Shares [Member]
Series C shares credited to company | shares	3,012,048