Net Loss Per Share - Computation of Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net loss	$ (11,310)	$ (12,307)	$ (45,550)	$ (25,506)
Denominator:
Weighted-average common shares outstanding, basic and diluted (in shares)	27,220,134	24,568,483	25,725,495	22,550,232
Net loss per common share, basic and diluted (in dollars per share)	$ (0.42)	$ (0.50)	$ (1.77)	$ (1.13)