Warrants

9 Months Ended

Sep. 30, 2018

Warrants and Rights Note Disclosure [Abstract]

Common Stock

Common stockholders are entitled to dividends if and when declared by the Company’s Board of Directors (the “Board of Directors”) subject to the prior rights of the preferred stockholders. As of September 30, 2018 and December 31, 2017, no dividends on common stock had been declared by the Board of Directors.

Common stock has been reserved for the following potential future issuances:



	September 30, 2018	December 31, 2017
	(unaudited)
Conversion of outstanding convertible preferred stock	58,264,577	58,264,577
Shares underlying outstanding stock options	7,717,070	7,391,052
Shares available for future stock option grants	509,584	1,698,790
Exercise and conversion of preferred stock warrants	7,636	7,636
Exercise of common stock warrants	40,538	313,741
Total	66,539,405	67,675,796

Repurchase of Common Stock

In April 2018, the Company repurchased 30,451 shares of outstanding common stock from certain employees at $10.80 per share for total consideration of $329,000. These shares were repurchased at a price that exceeded the fair value of the shares. The difference between the repurchase amount and the fair value of these shares were recorded as compensation expense of $157,000.

Warrants

In connection with a bank loan agreement with a financial institution in September 2013, the Company issued warrants to purchase 5,386 shares of Series A convertible preferred stock at an exercise price of $0.93 per share. In October 2014, the Company issued additional warrants to the same financial institution to purchase 4,965 shares of Series B convertible preferred stock at an exercise price of $3.16 per share. Both preferred stock warrants expire in ten years from issuance and are outstanding as of September 30, 2018 and December 31, 2017. These preferred stock warrants were converted to warrants to purchase common stock upon the consummation of IPO in October 2018.

In 2012, the Company issued to investors warrants to purchase 495,775 shares of common stock. The exercise price of the warrants is $0.14 per share and the warrants have a contractual term through September 2023. For the three and nine months ended September 30, 2018, 229,568 and 273,203 shares, respectively, were issued upon the exercise of warrants. For the three and nine months ended September 30, 2017, 49,284 shares were issued upon the exercise of warrants. As of September 30, 2018 and December 31, 2017, warrants to purchase 40,538 and 313,741 shares of common stock, respectively, remained outstanding. These common stock warrants were fully exercised prior to the consummation of IPO in October 2018.