Description of Business	3 Months Ended
Mar. 31, 2017
Accounting Policies [Abstract]
Description of Business	Description of Business Capnia, Inc. (the “Company”) was incorporated in the State of Delaware on August 25, 1999, and is located in Redwood City, California. On September 2, 2015, the Company established NeoForce, Inc. ("NFI"), a wholly owned subsidiary of the Company and through NFI, acquired substantially all of the assets of an unrelated privately held company NeoForce Group, Inc.("NeoForce"). NFI markets innovative pulmonary resuscitation solutions for the inpatient and ambulatory neonatal markets. On April 27, 2015, the Company established Capnia UK Limited, a wholly owned foreign subsidiary in the United Kingdom. On March 7, 2017, the Company completed the merger with Essentialis, Inc., a Delaware corporation, or Essentialis. After the merger, the Company's primary focus is transitioning to the development and commercialization of novel therapeutics for the treatment of rare diseases. Essentialis was a privately held, clinical stage biotechnology company focused on the development of breakthrough medicines for the treatment of rare metabolic 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 central nervous system diseases. Essentialis has tested Diazoxide Choline Controlled Release, or DCCR, tablets as a treatment for Prader-Willi syndrome, or PWS, a complex metabolic/neurobehavioral disorder. In addition, the Company continues to commercialize innovative medical devices to address unmet medical needs. The Company has two commercial products based on the Company's proprietary technologies, including those which utilize precision metering of gas flow. The most recent product to launch commercially is Serenz® Nasal Relief, or Serenz. In the United States, or U.S., the Company has concluded that Serenz is a Class I, 510(k) exempt device. Serenz is a proprietary handheld device that delivers non-inhaled CO₂ topically to the nasal mucosa. Serenz is used only when needed, and does not need to be used on a regular basis. The Company is also selling the CoSense® End-Tidal Carbon Monoxide (ETCO) Monitor, or CoSense, which measures ETCO and aids in the detection of excessive hemolysis, a condition in which red blood cells degrade rapidly. When present in neonates with jaundice, excessive hemolysis is a dangerous condition which can lead to adverse neurological outcomes. CoSense is 510(k) cleared for sale in the U.S. and received CE Mark certification for sale in the E.U. In addition, through NFI, the Company also develops and globally markets assets relating to innovative pulmonary resuscitation solutions for the inpatient and ambulatory neonatal markets. NFI’s primary product is the NeoPip T-piece resuscitator and related consumable, which delivers consistent pre-set inspiratory pressure and positive end-expiratory pressures. Other NFI products include temperature probes, scales, surgical tables and patient surfaces. Following the merger, the Company initiated a comprehensive review of strategic alternatives for the legacy products and product candidates, including Serenz® Allergy Relief, CoSense® ETCO Monitor, and its portfolio of innovative pulmonary resuscitation solutions for the neonatal market. The Company may also license elements of its Sensalyze Technology Platform to other companies that have complementary development or commercial capabilities. 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.

Description of Business

Capnia, Inc. (the “Company”) was incorporated in the State of Delaware on August 25, 1999, and is located in Redwood City, California.

On September 2, 2015, the Company established NeoForce, Inc. ("NFI"), a wholly owned subsidiary of the Company and through NFI, acquired substantially all of the assets of an unrelated privately held company NeoForce Group, Inc.("NeoForce"). NFI markets innovative pulmonary resuscitation solutions for the inpatient and ambulatory neonatal markets.

On April 27, 2015, the Company established Capnia UK Limited, a wholly owned foreign subsidiary in the United Kingdom.

On March 7, 2017, the Company completed the merger with Essentialis, Inc., a Delaware corporation, or Essentialis. After the merger, the Company's primary focus is transitioning to the development and commercialization of novel therapeutics for the treatment of rare diseases. Essentialis was a privately held, clinical stage biotechnology company focused on the development of breakthrough medicines for the treatment of rare metabolic 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 central nervous system diseases. Essentialis has tested Diazoxide Choline Controlled Release, or DCCR, tablets as a treatment for Prader-Willi syndrome, or PWS, a complex metabolic/neurobehavioral disorder.

In addition, the Company continues to commercialize innovative medical devices to address unmet medical needs. The Company has two commercial products based on the Company's proprietary technologies, including those which utilize precision metering of gas flow. The most recent product to launch commercially is Serenz® Nasal Relief, or Serenz. In the United States, or U.S., the Company has concluded that Serenz is a Class I, 510(k) exempt device. Serenz is a proprietary handheld device that delivers non-inhaled CO₂ topically to the nasal mucosa. Serenz is used only when needed, and does not need to be used on a regular basis.

The Company is also selling the CoSense® End-Tidal Carbon Monoxide (ETCO) Monitor, or CoSense, which measures ETCO and aids in the detection of excessive hemolysis, a condition in which red blood cells degrade rapidly. When present in neonates with jaundice, excessive hemolysis is a dangerous condition which can lead to adverse neurological outcomes. CoSense is 510(k) cleared for sale in the U.S. and received CE Mark certification for sale in the E.U. In addition, through NFI, the Company also develops and globally markets assets relating to innovative pulmonary resuscitation solutions for the inpatient and ambulatory neonatal markets. NFI’s primary product is the NeoPip T-piece resuscitator and related consumable, which delivers consistent pre-set inspiratory pressure and positive end-expiratory pressures. Other NFI products include temperature probes, scales, surgical tables and patient surfaces.

Following the merger, the Company initiated a comprehensive review of strategic alternatives for the legacy products and product candidates, including Serenz® Allergy Relief, CoSense® ETCO Monitor, and its portfolio of innovative pulmonary resuscitation solutions for the neonatal market. The Company may also license elements of its Sensalyze Technology Platform to other companies that have complementary development or commercial capabilities.

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.