Net Loss Per Share - Computation of Basic and Diluted Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net loss	$ (22,373)	$ (26,144)
Denominator:
Weighted average common shares outstanding - basic and diluted	88,880,658	62,546,295
Net loss per share - basic and diluted	$ (0.25)	$ (0.42)