Net Loss Per Share - Reconciliation of the Numerator and Denominator used in Computing Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net loss	$ (14,346)	$ (17,534)	$ (4,326)	$ (4,081)	$ (4,158)	$ (7,068)	$ (36,206)	$ (15,307)
Denominator:
Weighted-average shares outstanding — basic and diluted	22,931			21,961			22,686	21,738
Net loss per share — basic and diluted	$ (0.63)			$ (0.19)			$ (1.60)	$ (0.70)