Description of Business	3 Months Ended
Mar. 31, 2018
Accounting Policies [Abstract]
Description of Business	Note 1. Description of Business Soleno Therapeutics, Inc. (the “Company” or “Soleno”) was incorporated in the State of Delaware on August 25, 1999, and is located in Redwood City, California. The Company initially developed and commercialized neonatology devices and diagnostics. Additionally, the Company had a therapeutics platform based on its proprietary technology for precision metering of gas flow. Upon the acquisition of Essentialis Inc., or “Essentialis” through a merger, or the Merger, on March 7, 2017, pursuant to an Agreement and Plan of Merger, or the Merger Agreement, the Company initiated actions to divest, sell or dispose its device and diagnostics business activities and focus its research and transitioning to the development and commercialization of novel therapeutics for the treatment of rare diseases and on advancing the lead drug candidate acquired with Essentialis. Essentialis was a privately held, clinical stage biotechnology company focused on the development of breakthrough medicines for the treatment of rare diseases where there is increased mortality and risk of cardiovascular and endocrine complications. Prior to the Merger, Essentialis’s efforts were focused primarily on developing and testing product candidates that target the ATP-sensitive potassium channel, a metabolically regulated membrane protein whose modulation has the potential to impact a wide range of rare metabolic, cardiovascular, and CNS diseases. Essentialis has tested Diazoxide Choline Controlled Release Tablet, or DCCR, as a treatment for Prader-Willi Syndrome, or PWS, a complex metabolic/neurobehavioral disorder. DCCR has orphan designation for the treatment of PWS in the United States, or U.S., as well as in the European Union, or E.U. Subsequent to the merger with Essentialis, the Company explored opportunities to divest, sell or dispose of the NeoForce, CoSense, and Serenz businesses. The Company’s current research and development efforts are primarily focused on advancing its lead candidate, DCCR tablets for the treatment of PWS into late-stage clinical development, with a secondary emphasis on its joint venture with OAHL for the CoSense technology. CoSense is 510(k) cleared for sale in the U.S. and received CE Mark certification for sale in the E.U. The Company continues to separately evaluate alternatives for its Serenz portfolio. The operations directly related to the NeoForce, CoSense, and Serenz business are reported herein as discontinued operations and the related assets are reported as assets held for sale in accordance with ASC 205-20-45-10. The Company completed the sale of stock of its previously 100% wholly-owned subsidiaryNFI on July 18, 2017, pursuant to a Stock Purchase Agreement, or NFI Purchase Agreement, with NeoForce Holdings, Inc., or NFI Holdings, a 100% owned subsidiary of Flexicare Medical Limited, a privately held United Kingdom company, for $720,000 and adjustments for inventory and the current cash balances held at NFI. On October 6, 2017, the Company effected a one-for-five (1:5) reverse stock split of its then outstanding Common Stock and, accordingly, all common share and per share data are retrospectively restated to give effect of the split for all periods presented herein. On December 4, 2017, Soleno, and its wholly-owned subsidiary, Capnia, Inc., a Delaware corporation, or Capnia, entered into a joint venture with OptAsia Healthcare Limited, a Hong Kong company limited by shares, or OAHL, with the purpose of developing and commercializing medical monitors, including the CoSense^® End-Tidal Carbon Monoxide (ETCO) Monitor, or CoSense, that measure end-tidal carbon monoxide in breath to assist in the detection of excessive hemolysis in neonates, a condition in which red blood cells degrade rapidly and which can lead to adverse neurological outcomes.

Note 1. Description of Business

Soleno Therapeutics, Inc. (the “Company” or “Soleno”) was incorporated in the State of Delaware on August 25, 1999, and is located in Redwood City, California. The Company initially developed and commercialized neonatology devices and diagnostics. Additionally, the Company had a therapeutics platform based on its proprietary technology for precision metering of gas flow. Upon the acquisition of Essentialis Inc., or “Essentialis” through a merger, or the Merger, on March 7, 2017, pursuant to an Agreement and Plan of Merger, or the Merger Agreement, the Company initiated actions to divest, sell or dispose its device and diagnostics business activities and focus its research and transitioning to the development and commercialization of novel therapeutics for the treatment of rare diseases and on advancing the lead drug candidate acquired with Essentialis. Essentialis was a privately held, clinical stage biotechnology company focused on the development of breakthrough medicines for the treatment of rare diseases where there is increased mortality and risk of cardiovascular and endocrine complications. Prior to the Merger, Essentialis’s efforts were focused primarily on developing and testing product candidates that target the ATP-sensitive potassium channel, a metabolically regulated membrane protein whose modulation has the potential to impact a wide range of rare metabolic, cardiovascular, and CNS diseases. Essentialis has tested Diazoxide Choline Controlled Release Tablet, or DCCR, as a treatment for Prader-Willi Syndrome, or PWS, a complex metabolic/neurobehavioral disorder. DCCR has orphan designation for the treatment of PWS in the United States, or U.S., as well as in the European Union, or E.U.

Subsequent to the merger with Essentialis, the Company explored opportunities to divest, sell or dispose of the NeoForce, CoSense, and Serenz businesses. The Company’s current research and development efforts are primarily focused on advancing its lead candidate, DCCR tablets for the treatment of PWS into late-stage clinical development, with a secondary emphasis on its joint venture with OAHL for the CoSense technology. CoSense is 510(k) cleared for sale in the U.S. and received CE Mark certification for sale in the E.U. The Company continues to separately evaluate alternatives for its Serenz portfolio. The operations directly related to the NeoForce, CoSense, and Serenz business are reported herein as discontinued operations and the related assets are reported as assets held for sale in accordance with ASC 205-20-45-10.

The Company completed the sale of stock of its previously 100% wholly-owned subsidiaryNFI on July 18, 2017, pursuant to a Stock Purchase Agreement, or NFI Purchase Agreement, with NeoForce Holdings, Inc., or NFI Holdings, a 100% owned subsidiary of Flexicare Medical Limited, a privately held United Kingdom company, for $720,000 and adjustments for inventory and the current cash balances held at NFI.

On October 6, 2017, the Company effected a one-for-five (1:5) reverse stock split of its then outstanding Common Stock and, accordingly, all common share and per share data are retrospectively restated to give effect of the split for all periods presented herein.

On December 4, 2017, Soleno, and its wholly-owned subsidiary, Capnia, Inc., a Delaware corporation, or Capnia, entered into a joint venture with OptAsia Healthcare Limited, a Hong Kong company limited by shares, or OAHL, with the purpose of developing and commercializing medical monitors, including the CoSense^® End-Tidal Carbon Monoxide (ETCO) Monitor, or CoSense, that measure end-tidal carbon monoxide in breath to assist in the detection of excessive hemolysis in neonates, a condition in which red blood cells degrade rapidly and which can lead to adverse neurological outcomes.