v3.8.0.1
Document and Entity Information - shares
6 Months Ended
Oct. 31, 2017
Dec. 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 Oct. 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   45,212,760
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2018