Business Segment, Geographic, and Concentration Risk Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	$ (34,758)	$ (46,170)	$ (102,022)	$ (90,327)
Oncology Innovation Platform
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	(29,732)	(37,638)	(87,127)	(65,985)
Global Supply Chain Platform
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	(3,376)	(6,089)	(3,829)	(16,780)
Commercial Platform
Net loss attributable to Athenex, Inc.:
Total consolidated net loss attributable to Athenex, Inc.	$ (1,650)	$ (2,443)	$ (11,066)	$ (7,562)