| Document And Entity Information | Aug. 09, 2024 |
| Document Information [Line Items] | |
| Entity, Registrant Name | BioCardia, Inc. |
| Document, Type | S-1 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, Tax Identification Number | 23-2753988 |
| Entity, Address, Address Line One | 320 Soquel Way |
| Entity, Address, City or Town | Sunnyvale |
| Entity, Address, State or Province | CA |
| Entity, Address, Postal Zip Code | 94085 |
| Entity, Filer Category | Non-accelerated Filer |
| Entity, Small Business | true |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0000925741 |
