Stock-Based Compensation Expense - Common stock reserved for future issuance (Details) - shares	Jun. 30, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved	7,520,201	6,878,511
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved	585,448	640,479
Stock options issued and outstanding under the Equity Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved	6,223,110	5,754,005
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved	711,643	484,027