v3.5.0.1
Document And Entity Information - shares
6 Months Ended
Mar. 31, 2016
Jun. 23, 2016
Document And Entity Information [Abstract]    
Entity Registrant Name Oncobiologics, Inc.  
Entity Central Index Key 0001649989  
Trading Symbol ons  
Current Fiscal Year End Date --09-30  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   22,802,778
Document Type 10-Q  
Document Period End Date Mar. 31, 2016  
Amendment Flag false  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q2