CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 2,578,027	$ 1,692,658	$ 1,142,761
Costs and expenses:
Cost of revenue	529,320	449,358	358,903
Research and development	780,264	606,194	1,207,059
Sales and marketing	641,279	442,807	611,590
General and administrative	300,977	336,803	354,075
Total costs and expenses	2,251,840	1,835,162	2,531,627
Income (loss) from operations	326,187	(142,504)	(1,388,866)
Interest income	4,204	16,119	30,164
Interest expense and other income (expense), net	(9,420)	(635)	(2,137)
Income (loss) before provision for income taxes	320,971	(127,020)	(1,360,839)
Provision for income taxes	4,533	1,303	532
Net income (loss)	$ 316,438	$ (128,323)	$ (1,361,371)
Net income (loss) per share attributable to common stockholders:
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ 0.49	$ (0.22)	$ (3.24)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ 0.46	$ (0.22)	$ (3.24)
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	640,030	596,264	420,473
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	691,651	596,264	420,473