Net Loss Per Share of Common Stock - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net loss	$ (11,306)	$ (8,654)	$ (9,345)	$ (4,792)	$ (3,147)	$ (4,201)	$ (29,305)	$ (12,140)
Weighted-average number of common shares used to compute basic and diluted net loss per share (in shares)	24,803,452			3,712,876			24,596,788	3,638,905
Net loss per share, basic and diluted (in dollars per share)	$ (0.46)			$ (1.29)			$ (1.19)	$ (3.34)