Net Loss per Share- Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	12,452,792	12,012,308
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	10,300,285	8,968,131
Shares to be issued under the 2018 ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	1,873,627	1,500,500
RSUs issued and expected to vest
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	278,880	711,000
Shares available from conversion of note payable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares excluded from computation of diluted net income per share attributable to common stockholders (in shares)	0	832,677