| Document And Entity Information | Aug. 29, 2024 |
| Document Information [Line Items] | |
| Entity, Registrant Name | BioCardia, Inc. |
| Document, Type | S-1/A |
| 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 Description | The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine. |
| Amendment Flag | true |
| Entity, Central Index Key | 0000925741 |
