Equity Incentive Plans - Estimated Fair Value of Stock Offered Under ESPP (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, Minimum	81.90%	85.20%	84.60%
Volatility, Maximum	88.00%	89.80%	85.70%
Risk-free interest rate, Minimum	0.63%	0.31%	1.42%
Risk-free interest rate, Maximum	1.36%	1.69%	2.60%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 18 days	5 years 3 months 18 days	5 years 3 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months
Volatility, Minimum	103.10%	54.30%	52.90%
Volatility, Maximum	126.60%	125.50%	82.00%
Risk-free interest rate, Minimum	0.04%	0.08%	1.58%
Risk-free interest rate, Maximum	0.11%	1.59%	2.55%
Employee Stock Purchase Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		2 months 26 days	2 months 26 days
Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		6 months	6 months