Net Loss Per Share Attributable to Common Stockholders - Computation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Class of Stock [Line Items]
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	121,242	115,326	120,295	114,733
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	121,242	115,326	120,295	114,733
Net loss per share attributable to common stockholders, basic (in US dollar per share)	$ (0.14)	$ (0.51)	$ (0.67)	$ (0.95)
Net loss per share attributable to common stockholders, diluted (in US dollar per share)	$ (0.14)	$ (0.51)	$ (0.67)	$ (0.95)
Common Stock—Class A
Class of Stock [Line Items]
Net loss attributable to common stockholders, basic	$ (16,437)	$ (53,339)	$ (80,701)	$ (99,511)
Net loss attributable to common stockholders, diluted	$ (16,437)	$ (53,339)	$ (80,701)	$ (99,511)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	121,242	105,522	120,295	104,766
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	121,242	105,522	120,295	104,766
Net loss per share attributable to common stockholders, basic (in US dollar per share)	$ (0.14)	$ (0.51)	$ (0.67)	$ (0.95)
Net loss per share attributable to common stockholders, diluted (in US dollar per share)	$ (0.14)	$ (0.51)	$ (0.67)	$ (0.95)
Common Stock—Class B
Class of Stock [Line Items]
Net loss attributable to common stockholders, basic		$ (4,956)		$ (9,467)
Net loss attributable to common stockholders, diluted		$ (4,956)		$ (9,467)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)		9,804		9,967
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)		9,804		9,967
Net loss per share attributable to common stockholders, basic (in US dollar per share)		$ (0.51)		$ (0.95)
Net loss per share attributable to common stockholders, diluted (in US dollar per share)		$ (0.51)		$ (0.95)