| Document And Entity Information | Feb. 15, 2024 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Feb. 15, 2024 |
| Entity Registrant Name | Renalytix plc |
| Entity Central Index Key | 0001811115 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Securities Act File Number | 001-39387 |
| Entity Incorporation, State or Country Code | X0 |
| Entity Tax Identification Number | 00-0000000 |
| Entity Address, Address Line One | Finsgate |
| Entity Address, Address Line Two | 5-7 Cranwood Street |
| Entity Address, City or Town | London EC1V 9EE |
| Entity Address, Country | GB |
| Entity Address, Postal Zip Code | EC1V 9EE |
| City Area Code | +44 |
| Local Phone Number | 20 3139 2910 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Ordinary shares, nominal value £0.0025 per ordinary share |
| No Trading Symbol Flag | true |
| Security Exchange Name | NASDAQ |
| American Depositary Shares [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | American Depositary Shares, each representing two ordinary shares, nominal value £0.0025 per ordinary share |
| Trading Symbol | RNLX |
| Security Exchange Name | NASDAQ |
