Stockholders' Equity

12 Months Ended

Dec. 31, 2019

Stockholders’ Equity

Preferred Stock

We have 10,000,000 shares of preferred stock authorized for issuance, par value of $0.001 per share. As of December 31, 2019 and 2018, no shares of preferred stock were issued and outstanding.

Common Stock

On May 21, 2019, our stockholders approved and we filed an amendment to our Fifth Amended and Restated Certificate of Incorporation, as amended, to increase the total number of authorized shares of common stock from 50,000,000 to 100,000,000. Each holder of our common stock, par value of $0.001 per share, is entitled to one vote for each share of such stock held. As of December 31, 2019 and 2018, there were 45,272,088 and 42,078,164 shares of common stock issued and outstanding.

The following table presents common stock reserved for future issuance for the following equity instruments as of December 31, 2019 and 2018 (in thousands):


	December 31,
	2019	2018
Stock options and RSUs outstanding	4,692	4,033
Warrants to purchase common stock	28	28
Available for future grants under employee equity plans	4,926	1,684
Total common stock reserved for future issuance	9,646	5,745

Sale of Common Stock

At-the-Market Offerings

In May 2016, we entered into an at-the-market sales agreement (the ATM Sales Agreement) with Cantor Fitzgerald & Co. (Cantor) pursuant to which Cantor agreed to act as a sales agent in connection with sales of our common stock from time to time pursuant to an effective registration statement. In May 2016, we filed a registration on Form S-3, which was declared effective by the SEC on May 24, 2016, which included a prospectus covering the offering, issuance and sale of up to $25.0 million in gross aggregate proceeds of common stock from time to time, through Cantor as our sales agent. In the third quarter of 2017, we sold 1,550,880 shares of our common stock resulting in net proceeds of approximately $19.4 million, after deducting commissions and other offering expenses.

In December 2017, we filed a prospectus supplement (the 2017 ATM Prospectus), to our automatic “shelf” registration statement on Form S-3 registering the offering, issuance and sale of up to $75.0 million in gross aggregate proceeds of common stock pursuant to the ATM Sales Agreement. During the years ended December 31, 2019 and 2018, we sold 903,573 and 740,417 shares of common stock, respectively, resulting in net proceeds of approximately $42.6 million and $30.3 million, respectively, after deducting commissions and other offering costs. As of December 31, 2019, there were no amounts remaining for future sales under the 2017 ATM Prospectus.

Underwritten Public Offerings

In October 2017, we completed an underwritten public offering for the sale of 7,700,000 shares of our common stock. The shares were sold at an offering price of $37.50 per share. Net proceeds raised from the offering amounted to approximately $271.3 million, after deducting underwriting discounts and commissions and other offering expenses.

In August 2018, we completed an underwritten public offering for the sale of 6,000,000 shares of our common stock. The shares were sold at an offering price of $52.00 per share. Net proceeds raised from the offering amounted to approximately$292.9 million, after deducting underwriting discounts and commissions and other offering expenses.