XML 11 R1.htm IDEA: XBRL DOCUMENT v3.23.3
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2023
Oct. 20, 2023
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2023  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q3  
Trading Symbol CBIO  
Entity Registrant Name Catalyst Biosciences, Inc.  
Entity Central Index Key 0001124105  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   37,978,142
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity File Number 000-51173  
Entity Tax Identification Number 56-2020050  
Entity Address, Address Line One 12770 High Bluff Drive  
Entity Address, Address Line Two Suite 150  
Entity Address, City or Town San Diego  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 92130  
City Area Code 650  
Local Phone Number 266-8674  
Entity Interactive Data Current Yes  
Security Exchange Name NASDAQ  
Entity Incorporation, State or Country Code DE  
Document Quarterly Report true  
Document Transition Report false  
Title of 12(b) Security Common Stock  
Former Address [Member]    
Document Information [Line Items]    
Entity Address, Address Line One 611 Gateway Blvd.  
Entity Address, Address Line Two Suite 120  
Entity Address, City or Town South San Francisco  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 94080