DEI Document - shares
3 Months Ended
Apr. 30, 2019
May 31, 2019
Document Information [Line Items]    
Document Type 10-Q  
Document Fiscal Year Focus 2020  
Amendment Flag false  
Document Period End Date Apr. 30, 2019  
Document Fiscal Period Focus Q1  
Entity Registrant Name SMARTSHEET INC  
Entity Central Index Key 0001366561  
Current Fiscal Year End Date --01-31  
Entity Filer Category Non-accelerated Filer  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Small Business false  
Common Class A    
Document Information [Line Items]    
Entity Common Stock Shares Outstanding   74,527,425
Common Class B    
Document Information [Line Items]    
Entity Common Stock Shares Outstanding   32,037,234