Summary of Significant Accounting Policies - Summary of Weighted Average Assumptions Used to Compute Stock-Based Compensation Costs for Stock Options Granted (Detail) - Options to purchase common stock	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.00%	2.85%
Expected dividend yield		0.00%
Weighted average expected life	6 years 1 month 2 days	6 years 29 days
Volatility	80.76%	78.54%