XML 19 R1.htm IDEA: XBRL DOCUMENT v3.20.2
Cover Page - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2020
Sep. 03, 2020
Dec. 31, 2019
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Jun. 30, 2020    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Trading Symbol MEIP    
Entity Registrant Name MEI Pharma, Inc.    
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    
Entity Small Business true    
Title of 12(b) Security Common Stock    
Security Exchange Name NASDAQ    
Entity Interactive Data Current Yes    
Entity Address, State or Province CA    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Common Stock, Shares Outstanding   112,522,001  
Entity Public Float     $ 261.5