Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 11, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	ALRN
Entity Registrant Name	Aileron Therapeutics, Inc.
Entity Central Index Key	0001420565
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		90,823,597
Entity File Number	001-38130
Entity Tax Identification Number	13-4196017
Entity Address, Address Line One	285 Summer Street
Entity Address, Address Line Two	Suite 101
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02210
City Area Code	617
Local Phone Number	995-0900
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ