| Document and Entity Information | Sep. 09, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Sep. 9, 2021 |
| Entity Registrant Name | AEGLEA BIOTHERAPEUTICS, INC. |
| Entity Central Index Key | 0001636282 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
| Entity Incorporation, State or Country Code | DE |
| 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, State or Province | TX |
| Entity Address, Postal Zip Code | 78746 |
| City Area Code | 512 |
| Local Phone Number | 942-2935 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.0001 Par Value Per Share |
| Trading Symbol | AGLE |
| Security Exchange Name | NASDAQ |
