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Description of purchase price for shares of common stock purchased under employee stock purchase plan.

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Employee stock purchase plan number of shares initially authorized.

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Increase of common stock capital shares reserved for future issuance in each of calendar year.

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Minimum weekly period required to work for getting eligible to participate in employee stock purchase plan.

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Percentage of payroll deduction on eligible compensation.

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Percentage of units earned of units granted.

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Share based compensation arrangement by share based payment award average vesting period.

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Aggregate number of common shares reserved for future issuance.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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Description of terms of award under share-based payment arrangement.

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Amount of cost expensed and capitalized for award under share-based payment arrangement.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Number of non-vested options outstanding.

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Number of options vested.

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Weighted average grant-date fair value of options vested.

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Purchase price of common stock expressed as a percentage of its fair value.

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Equity Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to outstanding awards	2,278,789	3,537,014
Stock-based compensation cost capitalized	$ 1.6	$ 0.4	$ 0.1
Total intrinsic value of options exercised	$ 173.2	$ 243.8	$ 318.5
Options granted	0
Weighted average grant date fair value of options granted		$ 34.00	$ 19.80
Number of shares, vested	1,051,226
Number of options unvested	525,722
Contractual life	10 years
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term		6 years	6 years
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term		5 years	5 years
Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, average vesting term	4 years
Expected term	6 years
Non Employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, average vesting term	1 year
Expected term	5 years
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation expense related to stock options	$ 11.1
Unrecognized compensation expense expected to be recognized over weighted average period	1 year 7 months 6 days
Stock Options \| Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period	4 years
Stock Options \| Non Employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period	1 year
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense expected to be recognized over weighted average period	2 years 10 months 24 days
Total unrecognized compensation expense expected to be recognized	$ 220.5
Restricted Stock Units (RSUs) \| Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period	4 years
Restricted Stock Units (RSUs) \| Non Employee Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting period	1 year
Performance Share Units (PSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense expected to be recognized over weighted average period	1 year 10 months 24 days
Stock options vesting period	3 years
Total unrecognized compensation expense expected to be recognized	$ 19.9
Vesting term, description	Each PSU grant will vest in annual tranches over a three-year service period. Total units earned for grants made in 2021 may vary between 0% and 250% of the units granted based on the attainment of company-specific performance targets during the related three-year period and continued service.
Vesting percentage	250.00%
Performance Share Units (PSUs) \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage	0.00%
Performance Share Units (PSUs) \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Service period	3 years
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	5,315,780
Automatically increase percentage of aggregate number of shares of common stock outstanding	5.00%
Shares subject to outstanding awards	4,077,218
Shares available for future issuance	12,042,976
2006 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares subject to outstanding awards	1,178,424
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	996,709
Total unrecognized compensation expense related to stock options	$ 0.4
Contractual life	10 years
Expected term	6 months	6 months	6 months
Description of offering period for ESPP	Offering periods begin on August 1 and February 1 each year (or such other date determined by our Board of Directors or our Compensation and Leadership Development Committee).
Minimum weekly hours required to work for getting eligible to participate in ESPP	20 hours
Description of purchase price for shares of common stock purchased under ESPP	The purchase price for shares of common stock purchased under the ESPP is 85% of the lesser of the fair market value of the Company’s common stock on (i) the first day of the applicable offering period or (ii) the last day of the purchase period in the applicable offering period.
Percentage of purchase price for shares of common stock under fair value market	85.00%
Employee stock purchase plan number of shares initially authorized	10,102,525
2018 Employee Stock Purchase Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of payroll deduction on eligible compensation	15.00%
2018 Employee Stock Purchase Plan \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Automatically increase percentage of aggregate number of shares of common stock outstanding	1.00%
Percentage of payroll deduction on eligible compensation	1.00%
Increase of common stock capital shares reserved for future issuance in each of calendar year	1,000,000
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	2,509,441