7. Stockholders’ equity (deficit)

Common stock

As of December 31, 2019 and 2018, the Company’s certificate of incorporation, as amended and restated, authorized the Company to issue 150,000,000 shares and 75,000,000 shares of $0.0001 par value common stock, respectively. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. The holders of common stock, voting exclusively and as a separate class, have the exclusive right to vote for the election of directors of the Company. Common stockholders are entitled to receive dividends, as may be declared by the board of directors. Through December 31, 2019, no cash dividends had been declared or paid.

On June 24, 2019, the Company completed its IPO at which time the Company issued 6,612,500 shares of common stock, including the exercise in full by the underwriters of their option to purchase up to 862,500 additional shares of common stock, at a public offering price of $16.00 per share. The Company received $98,394, net of underwriting discounts and commissions, but before deducting offering costs payable by the Company, which were $2,942. Upon the closing of the IPO, all outstanding shares of convertible preferred stock converted into 21,056,136 shares of common stock (see Note 6). As of December 31, 2019 and December 31, 2018, there were 28,567,837 and 238,986 shares of common stock issued and outstanding, respectively.

The following shares of common stock were reserved for issuance as follows:


	December 31,
	2019	2018
Conversion of outstanding shares of preferred stock	—	21,056,136
Options outstanding under the 2018 Stock Option and Grant Plan	2,296,029	1,839,913
Options outstanding under the 2019 Stock Option and Incentive Plan	800,526	—
Options available for future grant	1,771,931	1,219,461
2019 Employee Stock Purchase Plan	269,364	—
	5,137,850	24,115,510

Undesignated preferred stock

As of December 31, 2019, the Company’s fourth amended and restated certificate of incorporation authorized the Company to issue up to 10,000,000 shares of undesignated preferred stock, par value $0.0001 per share. There were no undesignated preferred shares issued or outstanding as of December 31, 2019.

Restricted common stock

In March 2017, the Company issued an aggregate of 226,400 shares of restricted common stock under restricted stock agreements with the founders. Pursuant to the terms of the agreements, the restricted common stock was initially subject to a vesting schedule over a four-year period commencing in January 2017 and culminating in January 2021. During the vesting period, the Company has the right to repurchase up to all unvested shares at the amount paid if the relationship between the recipient and the Company ceases. Subject to the continued employment or other business relationship with the Company, all of the restricted common stock becomes fully vested within four years of the date of issuance.

In October 2017, 75,467 shares of restricted common stock were subject to repurchase by the Company when one of the founders terminated his relationship with the Company. The Company repurchased the shares in March 2018 for an immaterial amount and immediately reissued the shares to the remaining founders. In connection with the repurchase and reissuance of the shares, the Company amended the restricted stock agreements with the remaining founders such that the restricted common stock is now subject to a vesting schedule over a two-year period commencing in May 2018 and culminating in May 2020.

The Company accounted for the acceleration of vesting under the amended restricted stock agreement as a modification of the original awards and recognized the remaining unvested shares prospectively over the revised vesting period. The grant date fair value of restricted stock vested during the years ended December 31, 2019 and 2018 was insignificant.

In April, June and July 2019, the Company amended certain option grant agreements granted under the Company’s 2018 Stock Option and Grant Plan to allow the holders the right to early exercise unvested options, subject to a repurchase right held by the Company equal to the lesser of the original exercise price per share or the fair value of the shares on the repurchase date. The unvested shares issued as a result of the early exercise are deemed restricted stock pursuant to a restricted stock agreement and a vesting schedule identical to the vesting schedule of the original grant agreement. The proceeds related to unvested restricted common stock are recorded as liabilities until the stock vests, at which point they are reclassified to additional paid-in capital. Common shares issued for the early exercise of options are included in issued and outstanding shares.

The following table summarizes restricted stock activity since December 31, 2017:


		Grant-Date Fair
	Number of Shares	Value
Unvested restricted common stock as of December 31, 2017	226,400	$	—
Shares vesting	(146,210)		—
Unvested restricted common stock as of December 31, 2018	80,190		—
Early exercise of unvested stock options	491,207		0.65
Shares vesting	(416,248)		0.65
Unvested restricted common stock as of December 31, 2019	155,149	$	0.65

As of December 31, 2019, there were 155,149 shares of unvested restricted common stock subject to repurchase, consisting of 23,598 shares from unvested restricted common stock awards under restricted stock agreements with the founders and 131,551 shares from the early exercise of stock options.