Description of Business	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Change in Fiscal Year On December 8, 2017, the Board of Directors of Opiant Pharmaceuticals, Inc. (“Opiant" or the “Company”), acting pursuant to Section 5.1 of the Company’s Bylaws, approved a resolution changing the Company’s fiscal year-end from July 31 to December 31. As such, the end of the quarters in the new fiscal year do not coincide with the end of the quarters in the Company's previous fiscal years. The Company made this change to align its fiscal year end with other companies within its industry. Company Opiant is a specialty pharmaceutical company developing pharmacological treatments for substance use, addictive and eating disorders, primarily focused on using opioid antagonists. The Company was incorporated in the State of Nevada in June 2005 as Madrona Ventures, Inc. and, in September 2009, it changed its name to Lightlake Therapeutics Inc. In January 2016, the Company again changed its name to Opiant Pharmaceuticals, Inc. On October 2, 2017, the Company changed its state of incorporation from the State of Nevada to the State of Delaware pursuant to an Agreement and Plan of Merger, dated October 2, 2017 whereby the Company merged with and into its recently formed, wholly-owned Delaware subsidiary, Opiant Pharmaceuticals, Inc. Pursuant to the Agreement and Plan of Merger, (i) the Company merged with and into its Delaware subsidiary, (ii) the Company's separate corporate existence in Nevada ceased to exist, (iii) the Company's Delaware subsidiary became the surviving corporation, (iv) each share of the Company's common stock, $0.001 par value per share (the “Common Stock”), outstanding immediately prior to the effective time was converted into one fully-paid and non-assessable share of common stock of Opiant Pharmaceuticals, Inc., a Delaware corporation, $0.001 par value per share, and (v) the certificate of incorporation and bylaws of the Company's Delaware subsidiary were adopted as its certificate of incorporation and bylaws at the effective time of the merger. The merger and the Agreement and Plan of Merger were approved by the Company's Board of Directors and stockholders representing a majority of outstanding Common Stock. The Company developed NARCAN® (naloxone hydrochloride) Nasal Spray, a treatment to reverse opioid overdose. This product was conceived, developed, licensed and approved by the U.S. Food and Drug Administration (“FDA”) in November 2015. It is marketed by Adapt Pharma Operations Limited (“Adapt”), an Ireland based pharmaceutical company. The Company plans to replicate this relatively low cost, business strategy primarily through developing nasal opioid antagonists in the field of addictions and related disorders. The Company primarily aims to identify and progress those drug development opportunities that have the potential to file additional New Drug Applications (“NDA”) with the FDA within three to five years, with larger market opportunities and with the potential to self-commercialize in the fields of addictions and related disorders. The Company's current pipeline of product candidates includes pharmacological treatments for Bulimia Nervosa ("BN"), Alcohol Use Disorder ("AUD"), Opioid Use Disorder ("OUD") and a long acting Opioid Overdose Reversal ("OOR") product. We are also pursuing other treatment opportunities within the addiction space. The Company has not had a bankruptcy, receivership or similar proceeding. The Company is required to comply with all regulations, rules and directives of governmental authorities and agencies applicable to the clinical testing and manufacturing and sale of pharmaceutical products.

Description of Business

Change in Fiscal Year

On December 8, 2017, the Board of Directors of Opiant Pharmaceuticals, Inc. (“Opiant" or the “Company”), acting pursuant to Section 5.1 of the Company’s Bylaws, approved a resolution changing the Company’s fiscal year-end from July 31 to December 31. As such, the end of the quarters in the new fiscal year do not coincide with the end of the quarters in the Company's previous fiscal years. The Company made this change to align its fiscal year end with other companies within its industry.

Company

Opiant is a specialty pharmaceutical company developing pharmacological treatments for substance use, addictive and eating disorders, primarily focused on using opioid antagonists. The Company was incorporated in the State of Nevada in June 2005 as Madrona Ventures, Inc. and, in September 2009, it changed its name to Lightlake Therapeutics Inc. In January 2016, the Company again changed its name to Opiant Pharmaceuticals, Inc.

On October 2, 2017, the Company changed its state of incorporation from the State of Nevada to the State of Delaware pursuant to an Agreement and Plan of Merger, dated October 2, 2017 whereby the Company merged with and into its recently formed, wholly-owned Delaware subsidiary, Opiant Pharmaceuticals, Inc. Pursuant to the Agreement and Plan of Merger, (i) the Company merged with and into its Delaware subsidiary, (ii) the Company's separate corporate existence in Nevada ceased to exist, (iii) the Company's Delaware subsidiary became the surviving corporation, (iv) each share of the Company's common stock, $0.001 par value per share (the “Common Stock”), outstanding immediately prior to the effective time was converted into one fully-paid and non-assessable share of common stock of Opiant Pharmaceuticals, Inc., a Delaware corporation, $0.001 par value per share, and (v) the certificate of incorporation and bylaws of the Company's Delaware subsidiary were adopted as its certificate of incorporation and bylaws at the effective time of the merger. The merger and the Agreement and Plan of Merger were approved by the Company's Board of Directors and stockholders representing a majority of outstanding Common Stock.

The Company developed NARCAN® (naloxone hydrochloride) Nasal Spray, a treatment to reverse opioid overdose. This product was conceived, developed, licensed and approved by the U.S. Food and Drug Administration (“FDA”) in November 2015. It is marketed by Adapt Pharma Operations Limited (“Adapt”), an Ireland based pharmaceutical company. The Company plans to replicate this relatively low cost, business strategy primarily through developing nasal opioid antagonists in the field of addictions and related disorders. The Company primarily aims to identify and progress those drug development opportunities that have the potential to file additional New Drug Applications (“NDA”) with the FDA within three to five years, with larger market opportunities and with the potential to self-commercialize in the fields of addictions and related disorders.

The Company's current pipeline of product candidates includes pharmacological treatments for Bulimia Nervosa ("BN"), Alcohol Use Disorder ("AUD"), Opioid Use Disorder ("OUD") and a long acting Opioid Overdose Reversal ("OOR") product. We are also pursuing other treatment opportunities within the addiction space.

The Company has not had a bankruptcy, receivership or similar proceeding. The Company is required to comply with all regulations, rules and directives of governmental authorities and agencies applicable to the clinical testing and manufacturing and sale of pharmaceutical products.