On March 8, 2018, the Company filed a Registration Statement on Form S-3ASR (the “2018 Shelf Registration Statement”) covering the potential offering, issuance, and sale of an indeterminate amount of common stock, preferred stock, debt securities, warrants and/or units. In March 2019, the Company completed a follow-on offering under the 2018 Shelf Registration Statement in which the Company issued 5,663,750 shares of common stock at a price of $51.00 per share, including 738,750 shares sold directly to the underwriters upon exercise of their option to purchase up to 738,750 shares of the Company’s common stock within 30 days of the offering. During the year ended December 31, 2019, the Company received proceeds totaling approximately $271.2 million from the offering, net of underwriting discounts and commissions and offering expenses.

The Company has reserved shares of common stock, on an as-if-converted basis, for issuance as follows:

	December 31, 2019		December 31, 2018
Options and awards issued and outstanding		5,315,254		3,864,407
Shares available for issuance under 2015 Stock Option and Incentive Plan		685,435		904,785
Shares available for issuance under 2015 Employee Stock Purchase Plan		1,140,541		780,716
Total		7,141,230		5,549,908

As amended in November 2015, the Company's Certificate of Incorporation authorizes 5,000,000 shares of preferred stock at a par value of $0.0001 per share. As of December 31, 2019, and 2018, no preferred stock was issued or outstanding.