| Document and Entity Information | Jan. 31, 2025 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001674632 |
| Current Fiscal Year End Date | --12-31 |
| Document Type | 8-K |
| Document Period End Date | Jan. 31, 2025 |
| Entity Registrant Name | Beta Bionics, Inc. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-42491 |
| Entity Tax Identification Number | 47-5386878 |
| Entity Address, Address Line One | 11 Hughes |
| Entity Address, City or Town | Irvine |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92618 |
| City Area Code | (949) |
| Local Phone Number | 427-7785 |
| 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 | BBNX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
