v3.25.3
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2025
Nov. 10, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Sep. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Entity Registrant Name Semnur Pharmaceuticals, Inc.  
Entity Central Index Key 0001913577  
Entity File Number 001-41351  
Entity Tax Identification Number 98-1659463  
Entity Incorporation, State or Country Code DE  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
City Area Code (650)  
Local Phone Number 422-7515  
Entity Address, Address Line One 960 San Antonio Road  
Entity Address, City or Town Palo Alto  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 94303  
Entity Common Stock, Shares Outstanding   229,740,978
Common Stock [Member]    
Document Information [Line Items]    
Title of 12(b) Security Common stock, par value $0.0001 per share  
Trading Symbol SMNR  
Warrant [Member]    
Document Information [Line Items]    
Title of 12(b) Security Warrants to purchase one share of common stock, each at an exercise price of $11.50 per share  
Trading Symbol SMNRW