| Document And Entity Information | Mar. 10, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 10, 2022 |
| Entity Registrant Name | KALVISTA PHARMACEUTICALS, INC. |
| Entity Central Index Key | 0001348911 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-36830 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 20-0915291 |
| Entity Address, Address Line One | 55 Cambridge Parkway |
| Entity Address, Address Line Two | Suite 901E |
| Entity Address, City or Town | Cambridge |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02142 |
| City Area Code | 857 |
| Local Phone Number | 999-0075 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.001 par value per share |
| Trading Symbol | KALV |
| Security Exchange Name | NASDAQ |
