v3.10.0.1
Document And Entity Information - shares
6 Months Ended
Dec. 31, 2018
Feb. 05, 2019
Document Information [Line Items]    
Entity Registrant Name SYNTHESIS ENERGY SYSTEMS INC  
Entity Central Index Key 0001375063  
Trading Symbol symx  
Current Fiscal Year End Date --06-30  
Entity Filer Category Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company false  
Entity Small Business true  
Entity Common Stock, Shares Outstanding (in shares)   11,032,120
Document Type 10-Q  
Document Period End Date Dec. 31, 2018  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Amendment Flag false