| Document and Entity Information | Aug. 14, 2024 |
| Cover [Abstract] | |
| Security Exchange Name | NASDAQ |
| Amendment Flag | false |
| Entity Central Index Key | 0001420565 |
| Document Type | 8-K |
| Document Period End Date | Aug. 14, 2024 |
| Entity Registrant Name | Aileron Therapeutics, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-38130 |
| Entity Tax Identification Number | 13-4196017 |
| Entity Address, Address Line One | 12407 N. Mopac Expy. |
| Entity Address, Address Line Two | Suite 250 |
| Entity Address, Address Line Three | #390 |
| Entity Address, City or Town | Austin |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 78758 |
| City Area Code | (737) |
| Local Phone Number | 802-1989 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.001 par value per share |
| Trading Symbol | ALRN |
| Entity Emerging Growth Company | false |
