16. Subsequent Events

Merck Collaboration

On January 2, 2019, we entered into an Exclusive License and Research Collaboration Agreement (the “Collaboration Agreement”) with Merck Sharp & Dohme Corp. (“Merck”) to discover and develop certain proprietary influenza A/B antiviral agents. Under the terms of the Collaboration Agreement, Merck will fund research and development for the program, including clinical development, and will be solely responsible for worldwide commercialization of any products derived from the collaboration. We received an upfront payment of $4,000,000 and are eligible to receive milestone payments related to designated development, regulatory and sales milestones with the potential to receive up to $156,000,000, as well as royalties on product sales. The Collaboration Agreement contains certain termination provisions that can be invoked by either party.

Private Placement

On March 13, 2019, the Company closed a private placement of 1,602,283 shares of its common stock and received gross proceeds of $4,182,000, before deducting offering expenses and commissions, and net proceeds were approximately $3,674,000.

At-the-Market Sales

On March 20, 2019, the Company by written notice suspended at-the-market sales of its common stock pursuant to the Distribution Agreement, dated July 19, 2018 by and among the Company, Ladenburg, Barrington, and AGP. The Company also terminated the engagement of Barrington as a sales agent under the Distribution Agreement effective March 21, 2019. The Distribution Agreement remains in place with respect to AGP, subject to the suspension of sales discussed above until further notice is provided by the Company to AGP. In January 2019, we sold 80,000 shares of common stock under the Distribution Agreement and received net proceeds of approximately $344,000.