Stockholders' Equity - Summary of Shares of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Total reserved (shares)	32,934,776	22,728,991
Options to purchase common stock
Class of Stock [Line Items]
Total reserved (shares)	7,057,258	6,011,126
Shares available for future grant
Class of Stock [Line Items]
Total reserved (shares)	783,873	664,544
RSU's issued and expecting to vest
Class of Stock [Line Items]
Total reserved (shares)	0	1,043,300
Shares available for conversion of note payable
Class of Stock [Line Items]
Total reserved (shares)	832,677	1,282,052
Shares available for ATM offering
Class of Stock [Line Items]
Total reserved (shares)	23,176,492	13,003,664
2018 Employee Stock Purchase Plan
Class of Stock [Line Items]
Total reserved (shares)	1,084,476	724,305