Net Loss per Share - Computation of Denominators Used in Net Loss per Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic:
Weighted average common shares outstanding	46,885,424	44,517,134	46,803,659	41,314,044
Diluted:
Weighted average common shares outstanding - Basic	46,885,424	44,517,134	46,803,659	41,314,044
Denominator for diluted net loss per share	46,885,424	44,517,134	46,803,659	41,314,044