Common Stock

3 Months Ended

Mar. 31, 2019

Equity [Abstract]

Common Stock

8. Common Stock

The Company had reserved shares of common stock for future issuance as follows:

	March 31,
	2019
Options issued and outstanding		11,790,706
Shares available for future stock option grants		7,591,207
Restricted stock units		1,361,902
Common stock warrants		61,861
Total		20,805,676

At-the-Market Sales Agreement

In August 2017, the Company entered into an “at-the-market” sales agreement, as amended in February 2019, or the 2017 Sales Agreement, with Cowen, through which the Company may offer and sell shares of its common stock having an aggregate offering of up to $100.0 million through Cowen, as the Company’s sales agent. The Company will pay Cowen a commission of up to 3% of the gross proceeds of sales made through the arrangement. There were no sales of shares of common stock pursuant to the 2017 Sales Agreement during the year ended December 31, 2018 or the three months ended March 31, 2019. As of March 31, 2019, the Company had an aggregate of $81.5 million remaining for future sales under the 2017 Sales Agreement, subject to the continued effectiveness of its shelf registration statement on Form S-3 (Registration No. 333-219639) or an effective replacement shelf registration statement.