1. Organization and Nature of Business Aclaris Therapeutics, Inc. was incorporated under the laws of the State of Delaware in 2012. On July 17, 2015, Aclaris Therapeutics International Limited (ATIL) was established under the laws of the United Kingdom as a wholly-owned subsidiary of Aclaris Therapeutics, Inc. (together with ATIL referred to as the Company). The Company is a clinical -stage specialty pharmaceutical company focused on identifying, developing and commercializing innovative and differentiated drugs to address significant unmet needs in dermatology. The Companys lead drug candidate, A -101, is a proprietary high -concentration hydrogen peroxide topical solution that the Company is developing as a prescription treatment for seborrheic keratosis (SK), a common non -malignant skin tumor. The Company has completed three Phase 2 clinical trials of A-101 in patients with SK. Initial Public Offering On October 6, 2015, the Companys registration statement on Form S-1 relating to its initial public offering of its common stock (the IPO) was declared effective by the Securities and Exchange Commission (SEC). The Companys common stock began trading on The NASDAQ Global Select Market on October 7, 2015. The IPO closed on October 13, 2015, and 5,000,000 shares of common stock were sold at a price to the public of $11.00 per share, for aggregate gross proceeds of $55,000 . In addition, upon the closing of the IPO, all of the Companys outstanding convertible preferred stock was converted into an aggregate total of 11,677,076 shares of common stock. The conversion of the convertible preferred stock was a non-cash transaction which has been excluded from the Consolidated Statements of Cash Flows. On October 12, 2015, the underwriters of the IPO exercised in full their option to purchase additional shares, and on October 13, 2015, the Company sold 750,000 additional shares of common stock at a price to the public of $11.00 per share, for aggregate gross proceeds of $8,250. The Company paid underwriting d