Net Loss Per Share - 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, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net loss	$ (3,601)	$ (20,537)	$ (16,530)	$ (12,332)	$ (7,210)	$ (11,431)	$ (16,052)	$ (7,437)	$ (53,000)	$ (42,130)	$ (4,552)
Weighted-average shares used in computing basic net loss per share (in shares)	68,207	67,800	67,292	66,721	66,133	65,460	63,282	61,705	67,512	64,154	60,371
Weighted-average shares used in computing diluted net loss per share (in shares)	68,207	67,800	67,292	66,721	66,133	65,460	63,282	61,705	67,512	64,154	60,371
Basic net loss per share (in USD per share)	$ (0.05)	$ (0.30)	$ (0.25)	$ (0.18)	$ (0.11)	$ (0.17)	$ (0.25)	$ (0.12)	$ (0.79)	$ (0.66)	$ (0.08)
Diluted net loss per share (in USD per share)	$ (0.05)	$ (0.30)	$ (0.25)	$ (0.18)	$ (0.11)	$ (0.17)	$ (0.25)	$ (0.12)	$ (0.79)	$ (0.66)	$ (0.08)