v3.22.4
Cover Page - shares
 6 Months Ended
Dec. 31, 2022
Feb. 06, 2023
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Dec. 31, 2022  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q2  
Securities Act File Number 000-50484  
Trading Symbol MEIP  
Entity Registrant Name MEI Pharma, Inc.  
Entity Tax Identification Number 51-0407811  
Entity Central Index Key 0001262104  
Current Fiscal Year End Date --06-30  
Entity Filer Category Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company false  
Entity Shell Company false  
City Area Code 858  
Local Phone Number 369-7100  
Entity Small Business true  
Title of 12(b) Security Common Stock, $0.00000002 par value  
Security Exchange Name NASDAQ  
Entity Incorporation, State or Country Code DE  
Entity Address, Address Line One 11455 El Camino Real  
Entity Address, City or Town San Diego  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 92130  
Entity Interactive Data Current Yes  
Entity Bankruptcy Proceedings, Reporting Current true  
Entity Common Stock, Shares Outstanding   133,260,865