Net Loss Per Share - Schedule of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net loss	$ (16,879)	$ (8,935)	$ (25,268)	$ (18,106)
Weighted-average number of shares outstanding used in computing net loss per share, basic and diluted	12,206,747	9,963,851	11,872,326	9,273,735
Net loss per share, basic and diluted	$ (1.38)	$ (0.90)	$ (2.13)	$ (1.95)