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Stockholders' Equity - RSUs and Revest Shares (Details)		3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 cofounder shares	Dec. 31, 2021 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 39,378,000	$ 36,636,000	$ 114,378,000	$ 100,900,000
Signal Sciences Corp.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of cofounders with shares subject to revesting | cofounder						3
Shares held back for restricted stock awards, revesting period						2 years
Signal Sciences Corp. | Common Stock—Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares restricted for stock awards (in shares) | shares						896,499
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Stock-based compensation expense		27,800,000	23,000,000	$ 72,900,000	52,000,000
Modification expense		1,900,000	3,900,000	$ 1,900,000	3,900,000
RSUs | First Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				4 years
Award vesting percentage				25.00%
RSUs | Remaining Period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period				36 months
Revest Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		7,300,000	$ 11,000,000	$ 27,600,000	$ 32,900,000
Nonvested shares sold that remain unvested (in shares) | shares							224,124
Proceeds from nonvested shares sold	$ 10,700,000
Modification expense, incremental fair value		$ 0		$ 5,600,000

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