| Document and Entity Information | Jul. 28, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | SOLENO THERAPEUTICS INC |
| Amendment Flag | false |
| Entity Central Index Key | 0001484565 |
| Document Type | 8-K |
| Document Period End Date | Jul. 28, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-36593 |
| Entity Tax Identification Number | 77-0523891 |
| Entity Address, Address Line One | 203 Redwood Shores Pkwy |
| Entity Address, Address Line Two | Suite 500 |
| Entity Address, City or Town | Redwood City |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94065 |
| City Area Code | (650) |
| Local Phone Number | 213-8444 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.001 par value |
| Trading Symbol | SLNO |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
