Common Stock (Tables)

12 Months Ended

Dec. 31, 2018

Stockholders Equity Note [Abstract]

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

As of December 31, 2016, the Company had not reserved any shares of common stock for future issuance. As of December 31, 2018 and 2017, 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

	As of December 31,
	2018		2017
Redeemable convertible preferred stock, on an as-converted basis		—		15,870,559
Options issued and outstanding		1,122,677		195,668
Unvested restricted stock units		24,960		—
Options available for future grants		1,350,582		1,670,341
Shares available for issuance under the 2018 ESPP		275,030		—
Total		2,773,249		17,736,568