v3.26.1
Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Mar. 16, 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 STRO    
Entity Registrant Name SUTRO BIOPHARMA, INC.    
Entity Central Index Key 0001382101    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Entity Well-known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Small Business true    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity File Number 001-38662    
Entity Tax Identification Number 47-0926186    
Entity Address, Address Line One 111 Oyster Point Blvd    
Entity Address, City or Town South San Francisco    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 94080    
City Area Code 650    
Local Phone Number 881-6500    
Entity Common Stock, Shares Outstanding   16,567,238  
Security Exchange Name NASDAQ    
Title of 12(b) Security Common stock, $0.001 par value    
Document Annual Report true    
Document Transition Report false    
Entity Incorporation, State or Country Code DE    
Entity Interactive Data Current Yes    
Entity Public Float     $ 60.0
Documents Incorporated by Reference

Portions of the registrant’s definitive proxy statement to be filed for its 2026 Annual Meeting of Stockholders are incorporated by reference into Part III hereof. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the end of the fiscal year covered by this Annual Report on Form 10-K.

   
Auditor Firm ID 42    
Auditor Name Ernst & Young LLP    
Auditor Location San Mateo, California    
Auditor Opinion

Opinion on the Financial Statements

We have audited the accompanying balance sheets of Sutro Biopharma, Inc. (the Company) as of December 31, 2025 and 2024, the related statements of operations, comprehensive loss, 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.