Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 12, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	AGLE
Entity Registrant Name	AEGLEA BIOTHERAPEUTICS, INC.
Entity Central Index Key	0001636282
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Common Stock Shares Outstanding		48,015,892
Entity Public Float			$ 386.0
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	true
ICFR Auditor Attestation Flag	false
Title of 12(b) Security	Common Stock, $0.0001 Par Value Per Share
Security Exchange Name	NASDAQ
Entity File Number	001-37722
Entity Tax Identification Number	46-4312787
Entity Address, Address Line One	805 Las Cimas Parkway
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Austin
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
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Documents Incorporated by Reference [Text Block]	Portions of the Registrant’s Definitive Proxy Statement (“Proxy Statement”) relating to the 2021 Annual Meeting of Stockholders will be filed with the Commission within 120 days after the end of the Registrant’s 2020 fiscal year and is incorporated by reference into Part III of this Report.