Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Mar. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	8,317,187	6,549,848
Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	5,214,762	3,947,025
Warrants for Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,366,141	1,366,141
Awards Available Under 2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	672,070	467,024
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,064,214	769,658