Equity Incentive Plans - Summary of Estimated Fair Value of Employee Stock Options (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value Assumptions
Expected volatility, Minimum	81.20%	93.00%	81.00%	81.20%
Expected volatility, Maximum	81.80%	93.50%	82.50%	93.50%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (in years)	5 years 4 months 24 days	5 years 7 months 6 days
Risk-free interest rate		0.30%
Risk-free interest rate, Minimum	0.80%		0.50%	0.30%
Risk-free interest rate, Maximum	1.10%		1.10%	1.40%
Minimum
Fair Value Assumptions
Expected term (in years)			5 years 4 months 24 days	5 years 7 months 6 days
Maximum
Fair Value Assumptions
Expected term (in years)			5 years 6 months	6 years 1 month 6 days