Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 01, 2019
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	AGLE
Security Exchange Name	NASDAQ
Entity Registrant Name	AEGLEA BIOTHERAPEUTICS, INC.
Entity Central Index Key	0001636282
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity File Number	001-37722
Entity Tax Identification Number	46-4312787
Entity Address, Address Line One	901 S. MoPac Expressway
Entity Address, Address Line Two	Barton Oaks Plaza One
Entity Address, Address Line Three	Suite 250
Entity Address, City or Town	Austin
Title of 12(b) Security	Common Stock, $0.0001 Par Value Per Share
Entity Address, Postal Zip Code	78746
City Area Code	512
Local Phone Number	942-2935
Entity Address, State or Province	TX
Entity Incorporation, State or Country Code	DE
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Ex Transition Period	true
Document Transition Report	false
Document Quarterly Report	true
Entity Common Stock, Shares Outstanding		28,985,518