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	12 Months Ended
Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net loss allocable to common stockholders	$ (15,717)	$ (25,155)	$ (9,333)	$ (9,732)	$ 6,778	$ (9,527)	$ 526	$ (6,634)	$ (59,937)	$ (8,857)	$ (63,509)
Denominator:
Weighted-average shares used in computing net loss per share, basic and diluted									115,218	104,618	28,308
Net loss per share, basic and diluted	$ (0.13)	$ (0.22)	$ (0.08)	$ (0.09)					$ (0.52)	$ (0.08)	$ (2.24)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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