Stock-Based Compensation - Schedule of Assumptions Used in Estimation of Fair Value of Stock (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Black-Scholes fair value (in usd per share)	$ 158.02	$ 80.48	$ 4.98
Risk-free interest rate, minimum	0.50%	0.20%	1.50%
Risk-free interest rate, maximum	1.30%	1.50%	2.60%
Dividend yield	0.00%	0.00%	0.00%
Volatility, minimum	124.70%	116.00%	105.40%
Volatility, maximum	142.00%	152.20%	134.10%
Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	4 years 1 month 6 days	3 years 10 months 24 days	3 years 10 months 24 days
Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	7 years 7 months 6 days	7 years 6 months
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	0.10%	0.20%	1.20%
Risk-free interest rate, maximum	0.20%	2.60%	2.60%
Dividend yield	0.00%	0.00%	0.00%
Volatility, minimum	114.90%	66.60%	52.20%
Volatility, maximum	159.40%	189.70%	171.60%
ESPP | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Black-Scholes fair value (in usd per share)	$ 83.47	$ 2.57	$ 2.57
Expected term (in years)	6 months	6 months	6 months
ESPP | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Black-Scholes fair value (in usd per share)	$ 238.85	$ 92.67	$ 35.00
Expected term (in years)	2 years	2 years	2 years