Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net loss	$ (55,062)	$ (27,292)	$ (105,506)	$ (43,527)
Other comprehensive income:
Currency translation effects	45	0	45	0
Unrealized gain (loss) on marketable securities	(1)	4	13	4
Total comprehensive loss	(55,018)	(27,288)	(105,448)	(43,523)
Net loss attributable to noncontrolling interests	(488)	(435)	(1,031)	(544)
Comprehensive loss attributable to Zentalis	$ (54,530)	$ (26,853)	$ (104,417)	$ (42,979)