| Document and Entity Information | Aug. 10, 2022 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001888012 |
| Document Type | 8-K |
| Document Period End Date | Aug. 10, 2022 |
| Entity Registrant Name | HilleVax, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-41365 |
| Entity Tax Identification Number | 85-0545060 |
| Entity Address, Address Line One | 75 State Street |
| Entity Address, Address Line Two | Suite 100 - #9995 |
| Entity Address, City or Town | Boston |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02109 |
| City Area Code | (617) |
| Local Phone Number | 213-5054 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, $0.0001 par value per share |
| Trading Symbol | HLVX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
