Net Income (Loss) Per Common Share - Schedule of Basic and Diluted Net Income (Loss) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Numerator:
Net income (loss) attributable to Zentalis	$ (88,277)	$ (112,527)	$ (78,209)	$ (175,746)
Denominator:
Weighted average number of common shares outstanding for basic (in shares)	71,040	60,790	70,969	60,038
Weighted average number of common shares outstanding for diluted earnings per share (in shares)	71,040	60,790	70,969	60,038
Net loss per common share, basic (in dollars per share)	$ (1.24)	$ (1.85)	$ (1.10)	$ (2.93)
Net loss per common share, diluted (in dollars per share)	$ (1.24)	$ (1.85)	$ (1.10)	$ (2.93)