Document and Entity Information - shares
3 Months Ended
Sep. 30, 2018
Oct. 22, 2018
Document and Entity Information    
Entity Registrant Name OSI SYSTEMS INC  
Entity Central Index Key 0001039065  
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Amendment Flag false  
Current Fiscal Year End Date --06-30  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   18,153,123
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1