Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net loss	$ (37,509)	$ (53,373)	$ (75,067)	$ (49,329)
Net loss attributable to redeemable noncontrolling interests and noncontrolling interests	(891)	(4,912)	(1,580)	(1,556)
Net loss attributable to ATAI Life Sciences N.V. shareholders - basic	(36,618)	(48,461)	(73,487)	(47,773)
Net loss attributable to ATAI Life Sciences N.V. shareholders - diluted	$ (36,618)	$ (48,461)	$ (73,487)	$ (47,773)
Denominator:
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. Stockholders - basic	153,971,202	132,265,075	153,751,456	125,797,732
Weighted average common shares outstanding attributable to ATAI Life Sciences N.V. stockholders - diluted	153,971,202	132,265,075	153,751,456	125,797,732
Net loss per share attributable to ATAI Life Sciences N.V. stockholders - basic	$ (0.24)	$ (0.37)	$ (0.48)	$ (0.38)
Net loss per share attributable to ATAI Life Sciences N.V. stockholders - diluted	$ (0.24)	$ (0.37)	$ (0.48)	$ (0.38)