XML 22 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Mar. 01, 2021
Jun. 30, 2020
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2020    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Entity Registrant Name 89bio, Inc.    
Entity Central Index Key 0001785173    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Interactive Data Current Yes    
Current Fiscal Year End Date --12-31    
Entity Filer Category Non-accelerated Filer    
Entity Well-known Seasoned Issuer No    
Entity Public Float     $ 72,707,052
Entity Common Stock, Shares Outstanding   19,946,426  
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
Title of 12(b) Security Common stock, par value $0.001 per share    
Trading Symbol ETNB    
Security Exchange Name NASDAQ    
Entity File Number 001-39122    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 36-4946844    
Entity Address, Address Line One 142 Sansome Street    
Entity Address Address Line Two Second Floor    
Entity Address, City or Town San Francisco    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 94104    
City Area Code 415    
Local Phone Number 500-4614    
Document Annual Report true    
Document Transition Report false    
Documents Incorporated by Reference

Portions of the registrant’s definitive proxy statement relating to its 2021 Annual Meeting of Stockholders, to be held on or about June 2, 2021, are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated. Such 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.