v3.25.4
Debt - Additional Information (Detail)
€ / shares in Units, € in Thousands
 1 Months Ended 12 Months Ended
Sep. 30, 2025
USD ($)
shares
Apr. 30, 2024
EUR (€)
CommonStock
€ / shares
Aug. 31, 2022
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
May 02, 2025
USD ($)
Nov. 30, 2018
USD ($)
Nov. 30, 2018
EUR (€)
€ / shares
Debt Instrument [Line Items]                
Convertible promissory notes issued         $ 20,000,000      
Long-term debt, net       $ 0 14,133,000      
Embedded Derivative Gain Loss On Embedded Derivative Net       (20,300,000) (3,400,000)      
Debt Instrument, Face Amount         20,000,000      
Convertible promissory notes, outstanding       0 14,133,000      
Gain (loss) from change in fair value of the derivative liability       (20,300,000) (3,400,000)      
Number of debt convertible into common shares | CommonStock   16            
Principal Amount       $ 175,000        
Maturity Date       Aug. 01, 2026        
Prime Rate Percent       4.30%        
Accrued interest payable, percent       9.05%        
Gain (Loss) on Extinguishment of Debt       $ (1,317,000) 0      
Borrowing amount percentage     70.00%          
Hercules Loan Agreement                
Debt Instrument [Line Items]                
Long-term debt, net         21,500,000      
Convertible promissory notes, outstanding         21,500,000      
Interest expense       200,000 500,000      
Principal Amount       $ 1,400,000   $ 100,000    
Prepayment Fee       6.95%   0.50%    
Long-Term Investments and Receivables, Net, Total           $ 21,800,000    
Prime Rate Percent       4.05%        
Loan agreement description       In addition, the financial covenant under the Hercules Loan Agreement required, beginning on October 1, 2024, that the Company 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 had 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 was required to 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 had 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 would 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.        
Gain (Loss) on Extinguishment of Debt       $ 1,300,000        
Borrowing amount percentage     50.00%          
Market capitalization daily basis     $ 550,000,000          
Maximum [Member]                
Debt Instrument [Line Items]                
Convertible promissory notes issued             $ 1,200,000 € 1,000
Debt Instrument, Face Amount             $ 1,200,000 € 1,000
ATAI LIFE SCIENCES N.V. [Member]                
Debt Instrument [Line Items]                
Convertible notes conversion, shares issued | shares 6,185,904              
Fair value of ordinary shares $ 7,700,000              
Debt conversion price | € / shares   € 17           € 17
Face value of convertible notes | €   € 1           € 1
2020 Convertible Note Agreement [Member]                
Debt Instrument [Line Items]                
Convertible promissory notes issued         1,200,000      
Debt Instrument, Face Amount         1,200,000      
Fair value of derivative liabilities         $ 1,800,000