| Cover | Jun. 30, 2021 |
| Entity Addresses [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jun. 30, 2021 |
| Entity File Number | 001-31326 |
| Entity Registrant Name | Eloxx Pharmaceuticals, Inc. |
| Entity Central Index Key | 0001035354 |
| Entity Tax Identification Number | 84-1368850 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 480 Arsenal Way |
| Entity Address, Address Line Two | Suite 130 |
| Entity Address, City or Town | Watertown |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02451 |
| City Area Code | 781 |
| Local Phone Number | 577-5300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value per share |
| Trading Symbol | ELOX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Former Address [Member] | |
| Entity Addresses [Line Items] | |
| Entity Address, Address Line One | 950 Winter Street |
| Entity Address, City or Town | Waltham |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02451 |
