v3.7.0.1
Document And Entity Information - shares
9 Months Ended
Jun. 30, 2017
Aug. 11, 2017
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 Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   24,676,365
Document Type 10-Q  
Document Period End Date Jun. 30, 2017  
Amendment Flag false  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3