Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss	$ (5,698)	$ (3,169)	$ (5,318)	$ (6,002)	$ (8,867)	$ (11,320)
Denominator:
Weighted average shares outstanding, basic and diluted	26,521,861		24,118,620		25,858,076	24,025,136
Net loss per share, basic and diluted	$ (0.21)		$ (0.22)		$ (0.34)	$ (0.47)