| Document And Entity Information | Dec. 26, 2023 |
| Document Information [Line Items] | |
| Entity, Registrant Name | APPLIED MOLECULAR TRANSPORT INC. |
| Document, Type | 8-K |
| Document, Period End Date | Dec. 26, 2023 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, File Number | 001-39306 |
| Entity, Tax Identification Number | 81-4481426 |
| City Area Code | 650 |
| Local Phone Number | 392-0420 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | AMTI |
| Security Exchange Name | NASDAQ |
| Entity, Emerging Growth Company | false |
| Entity, Address, Address Line One | 1209 Orange Street |
| Entity, Address, City or Town | Wilmington |
| Entity, Address, State or Province | DE |
| Entity, Address, Postal Zip Code | 19801 |
| Amendment Flag | false |
| Entity, Central Index Key | 0001801777 |
