Organization and Description of Business, Merger with Apricus Biosciences, Inc. Reverse Stock Split - Narrative (Details)	9 Months Ended
Sep. 30, 2019
Organization And Description Of Business Merger With Apricus Biosciences Inc. Reverse Stock Split - Narrative
Reverse stock split	On January 24, 2019, Apricus Biosciences, Inc., a Nevada corporation ("Apricus"), completed a business combination with Seelos Therapeutics, Inc., a Delaware corporation ("Seelos"), in accordance with the terms of the Agreement and Plan of Merger Reorganization (the "Merger Agreement") entered into on July 30, 2018. Pursuant to the Merger Agreement, (i) a subsidiary of Apricus merged with and into Seelos, with Seelos (renamed as "Seelos Corporation") continuing as a wholly owned subsidiary of Apricus and the surviving corporation of the merger and (ii) Apricus was renamed as "Seelos Therapeutics, Inc." (the "Merger"). The Merger was accounted for as a reverse recapitalization under United States generally accepted accounting principles ("U.S. GAAP") because the primary assets of Apricus were nominal following the close of the Merger. Seelos was determined to be the accounting acquirer based upon the terms of the Merger and other factors, including: (i) Seelos' stockholders and other persons holding securities convertible, exercisable or exchangeable directly or indirectly for Seelos common stock owned the majority of Apricus immediately following the effective time of the Merger, (ii) Seelos holds the majority (four of five) of board seats of the combined company and (iii) Seelos' management holds all key positions in the management of the combined company. Accordingly, the historical financial statements of Seelos Therapeutics, Inc. became the Company's historical financial statements, including the comparative prior periods. All references in the unaudited condensed consolidated financial statements to the number of shares and per-share amounts of common stock have been retroactively restated to reflect the exchange rate.

Organization and Description of Business, Merger with Apricus Biosciences, Inc. Reverse Stock Split - Narrative (Details)

9 Months Ended

Sep. 30, 2019

Organization And Description Of Business Merger With Apricus Biosciences Inc. Reverse Stock Split - Narrative

Reverse stock split

On January 24, 2019, Apricus Biosciences, Inc., a Nevada corporation ("Apricus"), completed a business combination with Seelos Therapeutics, Inc., a Delaware corporation ("Seelos"), in accordance with the terms of the Agreement and Plan of Merger Reorganization (the "Merger Agreement") entered into on July 30, 2018. Pursuant to the Merger Agreement, (i) a subsidiary of Apricus merged with and into Seelos, with Seelos (renamed as "Seelos Corporation") continuing as a wholly owned subsidiary of Apricus and the surviving corporation of the merger and (ii) Apricus was renamed as "Seelos Therapeutics, Inc." (the "Merger"). The Merger was accounted for as a reverse recapitalization under United States generally accepted accounting principles ("U.S. GAAP") because the primary assets of Apricus were nominal following the close of the Merger. Seelos was determined to be the accounting acquirer based upon the terms of the Merger and other factors, including: (i) Seelos' stockholders and other persons holding securities convertible, exercisable or exchangeable directly or indirectly for Seelos common stock owned the majority of Apricus immediately following the effective time of the Merger, (ii) Seelos holds the majority (four of five) of board seats of the combined company and (iii) Seelos' management holds all key positions in the management of the combined company. Accordingly, the historical financial statements of Seelos Therapeutics, Inc. became the Company's historical financial statements, including the comparative prior periods. All references in the unaudited condensed consolidated financial statements to the number of shares and per-share amounts of common stock have been retroactively restated to reflect the exchange rate.