Share-Based Compensation - Schedule of Fair Value of Stock Options Estimated on Date of Grant Using Black-Scholes Option Pricing Model (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Common stock fair value	$ 18.86	$ 3.89	$ 16.50	$ 3.92
Risk-free interest rate	0.38%	1.47%	0.40%	1.50%
Expected volatility	75.17%	81.10%	76.08%	81.12%
Expected term (in years)	6 years	6 years 1 month 6 days	6 years	6 years 1 month 6 days