Net and Comprehensive Loss Per Share Attributable to Common Stockholders - Schedule of Weighted Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss per Share (Detail) - Weighted Average [Member] - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Options to purchase common stock	4,771,960	5,171,960
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Options to purchase common stock	600,000	317,562