Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net loss	$ (174,244)	$ (178,625)
Net income (loss) attributable to redeemable noncontrolling interests and noncontrolling interests	(6,436)	(8,782)
Net income attributable to ATAI Life Sciences N.V. shareholders - basic and diluted	$ (167,808)	$ (169,843)
Denominator:
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. stockholders - basic and diluted	138,265,859	93,019,072
Net income per share attributable to ATAI Life Sciences N.V. shareholders - basic and diluted	$ (1.21)	$ (1.83)