Redeemable Convertible Preferred Stock and Common Stock (Tables)

9 Months Ended

Sep. 30, 2018

Temporary Equity Disclosure [Abstract]

Schedule of Number of Shares of Common Stock Reserved for Future Issuance

The Company has reserved the following number of shares of common stock for future issuance upon the conversion of preferred stock, exercise of options or grant of equity awards:

	September 30, 2018		December 31, 2017
Redeemable convertible preferred stock, on    an as-converted basis		—		15,870,559
Options issued and outstanding		1,066,678		195,668
Unvested restricted stock units		24,960		—
Options available for future grants		1,413,610		1,670,341
Shares available for issuance under the 2018 ESPP		275,030		—
Total		2,780,278		17,736,568