Net Loss Per Share - Summary of Calculation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net loss	$ (25,155)	$ (9,527)	$ (44,220)	$ (15,635)
Denominator:
Weighted-average shares used in computing net loss per share, basic and diluted	116,681	106,884	114,064	103,035
Net loss per share, basic and diluted	$ (0.22)	$ (0.09)	$ (0.39)	$ (0.15)