Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss	$ (7,822)	$ (6,669)	$ (6,250)	$ (6,753)	$ (5,698)	$ (3,169)	$ (20,741)	$ (15,620)
Denominator:
Weighted average shares outstanding, basic and diluted	32,523,405			26,728,205			29,685,936	26,150,236
Net loss per share, basic and diluted	$ (0.24)			$ (0.25)			$ (0.70)	$ (0.60)