| Cover Page | Mar. 11, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 17, 2022 |
| Entity Registrant Name | ZOSANO PHARMA CORPORATION |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-36570 |
| Entity Tax Identification Number | 45-4488360 |
| Entity Address, Address Line One | 34790 Ardentech Court |
| Entity Address, City or Town | Fremont |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94555 |
| City Area Code | 510 |
| Local Phone Number | 745-1200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.0001 par value |
| Trading Symbol | ZSAN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001587221 |
