Stockholders’ Equity

6 Months Ended

Jun. 30, 2020

Stockholders' Equity Note [Abstract]

Securities Offerings

In July 2020, we entered into a securities purchase agreement (the “Securities Purchase Agreement”) for a private placement with a select group of institutional investors, pursuant to which we sold 5,139,610 units (the “Common Units”) and 790,710 units (the “Prefunded Warrant Units”), for an aggregate purchase price of $60.0 million. Each Common Unit consists of one share of our common stock plus a warrant to purchase 0.3 shares of common stock (the “Common Stock Warrants”), and each Prefunded Warrant Unit consists of one prefunded warrant to purchase one share of common stock (the “Prefunded Warrants”) plus 0.3 Common Stock Warrants. The Prefunded Warrant Units and the Common Units are collectively referred to

as the “Units” and each Unit has a purchase price of $10.1175. The Common Stock Warrants have an exercise price of $12.74 and a term of 3.5 years. The Prefunded Warrants became fully exercisable upon the closing date and have an exercise price of $0.001 per share.

The issuance of the securities sold under the Securities Purchase Agreement have not been registered under the Securities Act of 1933, as amended, or state securities laws and may not be offered or sold in the United States absent registration with the SEC or an applicable exemption from such registration requirements. We have agreed to file a registration statement with the SEC covering the resale of the shares of common stock issuable in connection with the Securities Purchase Agreement and upon exercise of the warrants.

In June 2018, we entered into an equity distribution agreement, (“Equity Distribution Agreement”), with Piper Jaffray & Co., (“Piper Jaffray”), pursuant to which we may sell shares of our common stock through an “at the market” equity offering program for up to $50.0 million in gross cash proceeds. Under the Equity Distribution Agreement, we will set the parameters for the sale of shares, including the number of shares to be issued, the time period during which sales are requested to be made, limitation on the number of shares that may be sold in any one trading day and any minimum price below which sales may not be made. We will be unable to sell shares under the Equity Distribution Agreement until a prospectus supplement relating to any sales under the Equity Distribution Agreement is filed with the SEC. As of June 30, 2020, no sales under our Equity Distribution Agreement have occurred.

Equity Incentive Plans

On January 1, 2020, in connection with our 2018 Equity Incentive Plan (the “2018 Plan”) annual increase provision, a total of 929,394 additional shares were automatically added to the shares authorized under the 2018 Plan. In June 2020, in conjunction with our annual meeting of stockholders, our stockholders approved an additional increase of 743,515 shares authorized under our 2018 Plan.

In January 2020, annual stock option grants totaling 1,026,950 shares with a weighted average exercise price of $3.25 per share were issued to eligible employees and board members.

Also in January 2020, we issued 156,328 shares of RSUs at a grant date fair value of $3.23 per share to certain employees in lieu of cash incentive compensation. Half of the shares underlying each RSU vested on June 30, 2020, with the remaining half scheduled to vest on December 31, 2020, subject to each grantee’s continued employment or service to the Company on the applicable vesting dates. In addition, upon a change in control as defined in the 2018 Plan, any unvested shares underlying the RSU will immediately vest.

Stock-Based Compensation Expense

We use the Black-Scholes option pricing model to estimate the fair value of stock options granted at the grant date. The fair value of RSUs is equal to the closing stock price on the date of grant. We recognize the fair value of stock-based compensation as compensation expense over the requisite service period, which is the vesting period. Stock-based compensation is classified in the Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) as follows (in thousands):



	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
	(unaudited)
Employee:
Research and development	$	716	$	422	$	1,225	$	762
General and administrative	507		248		972		631
Non-Employee:
Research and development	7		11		18		40
General and administrative	2		1		3		3
Total stock-based compensation expense	$	1,232	$	682	$	2,218	$	1,436