v3.19.1
Document and Entity Information - shares
9 Months Ended
Jan. 31, 2019
Mar. 10, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jan. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Trading Symbol KALV  
Entity Registrant Name KALVISTA PHARMACEUTICALS, INC.  
Entity Central Index Key 0001348911  
Current Fiscal Year End Date --04-30  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Common Stock, Shares Outstanding   17,247,348