Debt - Additional Information (Detail) € / shares in Units, $ / shares in Units, € in Thousands							1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Jul. 31, 2022 USD ($)	Jul. 31, 2022 EUR (€) € / shares	May 31, 2022 USD ($)	May 31, 2022 EUR (€) € / shares	Jun. 10, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Aug. 31, 2022 USD ($)	Sep. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2022 shares	Sep. 30, 2021 USD ($) shares	Sep. 30, 2022 USD ($) $ / shares	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 EUR (€) € / shares	Sep. 30, 2022 EUR (€)	Feb. 28, 2022	Dec. 31, 2021 USD ($)	Jun. 30, 2021 $ / shares	Jun. 30, 2021 € / shares	May 31, 2021 USD ($)	Jan. 01, 2021 USD ($)	Dec. 01, 2020 USD ($)	Oct. 31, 2020 USD ($) $ / shares	Oct. 31, 2020 EUR (€)	Mar. 16, 2020 USD ($)	Nov. 30, 2018 USD ($)	Nov. 30, 2018 EUR (€)	Oct. 31, 2018 USD ($)	Oct. 31, 2018 EUR (€)
Debt Instrument [Line Items]
Convertible promissory notes issued								$ 15,000,000			$ 15,000,000
Long-term debt, net								$ 14,621,000			$ 14,621,000						$ 0
Debt conversion price | (per share)																		$ 1,654	€ 1,350
Maturity Date								Aug. 01, 2026			Aug. 01, 2026				Aug. 01, 2026
Prime Rate Percent								4.55%			4.55%				4.55%
Cash proceeds from certain permitted sources											$ 175,000,000.0
Accrued interest payable, percent								8.55%			8.55%				8.55%
Interest expense												$ 200,000
Amortization of debt discount											$ 0	192,000
Fair value amount of convertible promissory note								$ 16,800,000			16,800,000
General and administrative expense								$ 19,419,000		$ 20,264,000	54,623,000	$ 66,868,000
Second Tranche Funding [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																				$ 5,000,000.0
Common Stock [Member]
Debt Instrument [Line Items]
Stock issued during period, convertible share | shares								3,360,000	960,000	4,838,176
ATAI LIFE SCIENCES N.V. [Member]
Debt Instrument [Line Items]
Debt conversion price | $ / shares																							$ 17.00
Face value of convertible notes | €																								€ 1
Perception March 2020 Notes [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																									$ 3,900
Convertible promissory notes, interest rate																									5.00%
Fair value of ordinary shares					$ 600,000
Perception December 2020 Convertible Note Agreement [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																						$ 12,000,000.0
Convertible promissory notes, interest rate																5.00%
Fair value of derivative liabilities						$ 400,000
Proceeds from licensing and collaboration arrangement					20,000,000.0
Gain from change in fair value of the derivative liability					41,000
Loss on extinguishment of notes					500,000
Debt carrying value					2,700,000
Fair value of ordinary shares					2,200,000
Gain (loss) from change in fair value of the derivative liability					$ 41,000
Perception December 2020 Convertible Note Agreement [Member] | Series A Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible notes conversion, shares issued | shares					6,456,595
Perception December 2020 Convertible Note Agreement [Member] | First Tranche Funding [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued						$ 6,200,000															$ 800,000	$ 7,000,000.0
Perception December 2020 Convertible Note Agreement [Member] | Second Tranche Funding [Member]
Debt Instrument [Line Items]
Fair value of derivative liabilities								$ 300,000			300,000
Perception December 2020 Convertible Note Agreement [Member] | ATAI LIFE SCIENCES N.V. [Member] | Series A Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible notes conversion, shares issued | shares					5,403,791
Perception December 2020 Convertible Note Agreement [Member] | ATAI LIFE SCIENCES N.V. [Member] | Second Tranche Funding [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																				4,200,000
Perception December 2020 Convertible Note Agreement [Member] | Sonia Weiss Pick And Family [Member] | Series A Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible notes conversion, shares issued | shares					440,415
Perception December 2020 Convertible Note Agreement [Member] | Sonia Weiss Pick And Family [Member] | Second Tranche Funding [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																				300
Perception December 2020 Convertible Note Agreement [Member] | Other Investors [Member] | Series A Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible notes conversion, shares issued | shares					584,580
Perception December 2020 Convertible Note Agreement [Member] | Other Investors [Member] | Second Tranche Funding [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																				400
Perception December 2020 Convertible Note Agreement [Member] | Apeiron [Member] | Series A Preferred Stock [Member]
Debt Instrument [Line Items]
Convertible notes conversion, shares issued | shares					27,809
Perception December 2020 Convertible Note Agreement [Member] | Apeiron [Member] | Second Tranche Funding [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																				$ 200,000
Perception December 2020 Convertible Note Agreement [Member] | Qualified Sale of Preferred Stock [Member]
Debt Instrument [Line Items]
Minimum proceeds expected from sale of preferred stock for debt conversion											$ 5,000,000.0
Debt conversion price, discount percentage											25.00%
Perception December 2020 Convertible Note Agreement [Member] | Licensing Transaction [Member]
Debt Instrument [Line Items]
Minimum licensing transaction for debt conversion											$ 5,000.0
Debt conversion price | $ / shares								$ 0.75			$ 0.75
Debt conversion price, threshold percentage						75.00%
Perception December 2020 Convertible Note Agreement [Member] | Change In control [Member]
Debt Instrument [Line Items]
Debt conversion price | $ / shares								$ 0.75			$ 0.75
Two Thousand Eighteen Convertible Note Agreement [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued								$ 100,000			$ 100,000				€ 100											$ 200,000	€ 200	$ 1,000,000.0	€ 800
Debt conversion price | € / shares		€ 17.00		€ 17.00										€ 17.00
Fair value of ordinary shares	$ 4,600,000	€ 4,600	$ 4,600,000	€ 4,600									$ 6,900,000	€ 5,800
Less: unamortized end of term charge						$ 1,200,000
Two Thousand Eighteen Convertible Note Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																										$ 1,200,000	€ 1,000
Two Thousand Eighteen Convertible Note Agreement [Member] | Apeiron [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																							$ 600,000	500
Two Thousand Eighteen Convertible Note Agreement [Member] | Other Shareholder [Member]
Debt Instrument [Line Items]
Convertible promissory notes issued																							$ 400,000	€ 300
Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Interest expense								$ 100,000			$ 100,000
Line Of Credit							$ 40,000,000.0
Borrowing Amount Percentage							33.00%
Market capitalization daily basis							$ 600,000,000.0
Loan Agreement description											In addition, the financial covenant under the Loan Agreement requires that beginning on the later of (i) July 1, 2023 and (ii) the date on which the aggregate outstanding amount borrowed under the 2022 Term Loan Facility is equal to or greater than $40.0 million, the Company shall maintain Qualified Cash in an amount no less than the sum of (1) 33% 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, that the financial covenant shall not apply on any day that the Company's market capitalization is at least $600.0 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%
Principal Amount							$ 175,000,000.0
Increments							5,000,000.0
Hercules Loan Agreement [Member] | Tranche 1
Debt Instrument [Line Items]
Long-term debt, net							15,000,000.0
Hercules Loan Agreement [Member] | Tranche 1A
Debt Instrument [Line Items]
Term loan advance							15,000,000.0
Hercules Loan Agreement [Member] | Tranche 1B
Debt Instrument [Line Items]
Term loan advance							20,000,000.0
Hercules Loan Agreement [Member] | Tranche 1C
Debt Instrument [Line Items]
Term loan advance							25,000,000.0
Hercules Loan Agreement [Member] | Tranche 2
Debt Instrument [Line Items]
Term loan advance							15,000,000.0
Hercules Loan Agreement [Member] | Tranche 3
Debt Instrument [Line Items]
Term loan advance							$ 100,000,000.0
Prepayment occurs on or prior to the first anniversary[Member] | Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment Principal Amount Percentage							2.00%
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							1.00%
Prepayment occurs after the second anniversary [Member] | Hercules Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment Principal Amount Percentage							0.50%