| Document and Entity Information | Sep. 11, 2023 |
| Document And Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Sep. 11, 2023 |
| Entity Registrant Name | Dianthus Therapeutics, Inc. /DE/ |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-38541 |
| Entity Tax Identification Number | 81-0724163 |
| Entity Address, Address Line One | 7 Times Square |
| Entity Address, Address Line Two | 43rd Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10036 |
| City Area Code | 929 |
| Local Phone Number | 999-4055 |
| Entity Information, Former Legal or Registered Name | Magenta Therapeutics, Inc. |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value |
| Trading Symbol | DNTH |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Current Fiscal Year End Date | --12-31 |
| Entity Central Index Key | 0001690585 |
| Amendment Flag | false |
| Former Address [Member] | |
| Document And Entity Information [Line Items] | |
| Entity Address, Address Line One | 300 Technology Square |
| Entity Address, Address Line Two | 8th Floor |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
