XML 11 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Document and Entity Information - shares
 6 Months Ended
Mar. 31, 2021
Apr. 30, 2021
Cover [Abstract]    
Entity Registrant Name INNOVATIVE SOLUTIONS & SUPPORT INC  
Entity Central Index Key 0000836690  
Document Type 10-Q  
Document Period End Date Mar. 31, 2021  
Amendment Flag false  
Current Fiscal Year End Date --09-30  
Entity Current Reporting Status Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   17,241,872
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q2  
Entity Interactive Data Current Yes  
Title of 12(b) Security Common Stock, par value $0.001 per share  
Security Exchange Name NASDAQ  
Document Quarterly Report true  
Document Transition Report false  
Trading Symbol ISSC