v3.7.0.1
Document and Entity Information - shares
3 Months Ended
Jul. 31, 2017
Sep. 06, 2017
Document And Entity Information    
Entity Registrant Name PEREGRINE PHARMACEUTICALS INC  
Entity Central Index Key 0000704562  
Document Type 10-Q  
Document Period End Date Jul. 31, 2017  
Amendment Flag false  
Current Fiscal Year End Date --04-30  
Is Entity a Well-known Seasoned Issuer? No  
Is Entity a Voluntary Filer? No  
Is Entity's Reporting Status Current? Yes  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   45,096,081
Document Fiscal Period Focus Q1  
Document Fiscal Year Focus 2018