Summary of Significant Accounting Policies - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accounting Policies [Abstract]
Net loss	$ (8,007)	$ (8,952)	$ (44,124)	$ (22,010)
Weighted average common stock outstanding used to compute net loss per share, basic and diluted (in shares)	30,764,354	1,054,794	20,249,580	911,873
Net loss per share, basic and diluted (in USD per share)	$ (0.26)	$ (8.49)	$ (2.18)	$ (24.14)