Document and Entity Information - shares
 3 Months Ended
Dec. 31, 2019
Jan. 31, 2020
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Dec. 31, 2019  
Document Fiscal Year Focus 2020  
Document Fiscal Period Focus Q1  
Entity Registrant Name SONIC FOUNDRY INC  
Entity Central Index Key 0001029744  
Current Fiscal Year End Date --09-30  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   6,786,321
Entity Shell Company false