15. Subsequent Events

On August 1, 2019, the Company entered into a Distribution Agreement (the “Distribution Agreement”) with J.P. Morgan Securities LLC, Jefferies LLC and SVB Leerink LLC (the “Sales Agents”), pursuant to which the Company may issue and sell, from time to time, shares of its common stock having an aggregate offering price of up to $100.0 million through the Sales Agents, subject to the effectiveness of the Company’s registration statement on Form S-3 filed on August 1, 2019. The Sales Agents may sell common stock by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) of the Securities Act of 1933, as amended, including sales made directly on or through the Nasdaq Global Select Market or any other existing trade market for the common stock, in negotiated transactions at market prices prevailing at the time of sale or at prices related to prevailing market prices, or any other method permitted by law. The Sales Agents will be entitled to receive 3.0% of the gross sales price per share of common stock sold under the Distribution Agreement. As of the date of these financial statements, no shares of common stock have been issued and sold pursuant to the Distribution Agreement.