v3.26.1
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2025
Mar. 31, 2026
Jun. 30, 2025
Document and Entity Information      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2025    
Document Transition Report false    
Entity File Number 001-35737    
Entity Registrant Name NORTHWEST BIOTHERAPEUTICS INC    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 94-3306718    
Entity Address, Address Line One 4800 Montgomery Lane    
Entity Address, Address Line Two Suite 800    
Entity Address, City or Town Bethesda    
Entity Address, State or Province MD    
Entity Address, Postal Zip Code 20814    
City Area Code 240    
Local Phone Number 497-9024    
Title of 12(b) Security Common Stock, par value $0.001 per share    
Trading Symbol NWBO    
Security Exchange Name NONE    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers 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 false    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity Public Float     $ 340,239,000
Entity Common Stock, Shares Outstanding   1,606,857,011  
Entity Central Index Key 0001072379    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2025    
Current Fiscal Year End Date --12-31    
Amendment Flag false    
Auditor Name Cherry Bekaert LLP    
Auditor Firm ID 677    
Auditor Location Nashville, Tennessee