| Cover | Mar. 21, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 21, 2023 |
| Entity Registrant Name | APPLIED MOLECULAR TRANSPORT INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39306 |
| Entity Tax Identification Number | 81-4481426 |
| Entity Address, Address Line One | 450 East Jamie Court |
| Entity Address, City or Town | South San Francisco |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94080 |
| 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, par value $0.0001 per share |
| Trading Symbol | AMTI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001801777 |
| Amendment Flag | false |
