Acquisition by Zevra	9 Months Ended
Sep. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisiton by ZEVRA	2. ACQUISITION BY ZEVRA On August 30, 2023, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Zevra Therapeutics, Inc., a Delaware corporation (“Zevra”) and Aspen Z Merger Sub, Inc., a Delaware corporation and an indirect wholly-owned subsidiary of Zevra (“Merger Sub”), pursuant to which, subject to the terms and conditions of the Merger Agreement, Merger Sub will merge with and into the Company, with the Company surviving the merger as an indirect wholly-owned subsidiary of Zevra (the “Merger”). Pursuant to the Merger Agreement, and upon the terms and subject to the conditions described therein, at the effective time of the Merger (the “Effective Time”), each issued and outstanding share of common stock of the Company (“Acer Common Stock”) (other than (i) shares held in the Company’s treasury or shares owned directly or indirectly by Zevra, Merger Sub or any wholly-owned subsidiary of Acer and (ii) any shares held by any holder who properly demands appraisal of such shares under Delaware law) converted automatically into and represent the right to receive (a) 0.1210 of a share of common stock of Zevra (“Zevra Common Stock”) and (b) one non-transferable contingent value right (a “CVR”) issued by Zevra, which represents the right to receive one or more contingent payments, if any, upon the achievement of certain milestones, subject to and in accordance with the terms of a contingent value rights agreement (the “CVR Agreement”) (collectively, the “Merger Consideration”). The stockholders approved and adopted the Merger Agreement at the special meeting of stockholders of the Company held on November 8, 2023, at 11:00 a.m. Eastern Time (the “Special Meeting”). On November 17, 2023, the Merger was completed and the Company is now an indirect wholly-owned subsidiary of Zevra.

Acquisition by Zevra

9 Months Ended

Sep. 30, 2023

Business Combination and Asset Acquisition [Abstract]

ACQUISITION BY ZEVRA

On August 30, 2023, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Zevra Therapeutics, Inc., a Delaware corporation (“Zevra”) and Aspen Z Merger Sub, Inc., a Delaware corporation and an indirect wholly-owned subsidiary of Zevra (“Merger Sub”), pursuant to which, subject to the terms and conditions of the Merger Agreement, Merger Sub will merge with and into the Company, with the Company surviving the merger as an indirect wholly-owned subsidiary of Zevra (the “Merger”).

Pursuant to the Merger Agreement, and upon the terms and subject to the conditions described therein, at the effective time of the Merger (the “Effective Time”), each issued and outstanding share of common stock of the Company (“Acer Common Stock”) (other than (i) shares held in the Company’s treasury or shares owned directly or indirectly by Zevra, Merger Sub or any wholly-owned subsidiary of Acer and (ii) any shares held by any holder who properly demands appraisal of such shares under Delaware law) converted automatically into and represent the right to receive (a) 0.1210 of a share of common stock of Zevra (“Zevra Common Stock”) and (b) one non-transferable contingent value right (a “CVR”) issued by Zevra, which represents the right to receive one or more contingent payments, if any, upon the achievement of certain milestones, subject to and in accordance with the terms of a contingent value rights agreement (the “CVR Agreement”) (collectively, the “Merger Consideration”).

The stockholders approved and adopted the Merger Agreement at the special meeting of stockholders of the Company held on November 8, 2023, at 11:00 a.m. Eastern Time (the “Special Meeting”). On November 17, 2023, the Merger was completed and the Company is now an indirect wholly-owned subsidiary of Zevra.