Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2025	Feb. 20, 2026	Jun. 30, 2025
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Trading Symbol	BBNX
Current Fiscal Year End Date	--12-31
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-42491
Entity Registrant Name	BETA BIONICS, INC.
Entity Central Index Key	0001674632
Entity Incorporation, State or Country Code	DE
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
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		44,382,146
Entity Public Float			$ 631,998,349
Share Price, per share			$ 14.56
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
ICFR Auditor Attestation Flag	false
Entity Voluntary Filers	No
Document Financial Statement Error Correction [Flag]	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s definitive proxy statement relating to its 2026 annual meeting of stockholders (Proxy Statement) are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. The Proxy Statement will be filed with the U.S. Securities and Exchange Commission within 120 days after the end of the fiscal year to which this report relates.
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, California
Auditor Opinion [Text Block]	Opinion on the Financial Statements We have audited the accompanying balance sheets of Beta Bionics, Inc.(the Company) as of December 31, 2025 and 2024, the related statements of operations and comprehensive loss, convertible preferred stock and stockholders' equity (deficit) and cash flows for each of the two years in the period ended December 31, 2025, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the two years in the period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles.

Beta Bionics, Inc. 10-K