Business Segment, Geographic, and Concentration Risk Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	$ (19,429)	$ (35,233)
Oncology Innovation Platform
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	(958)	(27,603)
Global Supply Chain Platform
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	(5,986)	(767)
Commercial Platform
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	$ (12,485)	$ (6,863)