Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Jun. 30, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares as percentage of common shares outstanding	5.00%
Number of shares reserved for future issuance (in shares)	12,562,263
Accrued and other liabilities, related to shares held by employees and directors that were subject to repurchase	$ 2.8	$ 2.8
Other long term liabilities, related to shares held by employees and directors that were subject to repurchase	$ 2.5	$ 3.9
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	4 years
Stock options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period, weighted average grant date fair value (in dollars per share)	$ 20.01
Unrecognized stock based compensation expense	$ 91.8
Unrecognized stock based compensation expense, weighted average recognition period (in years)	2 years 336 days
Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	4 years
Unrecognized stock based compensation expense	$ 55.1
Unrecognized stock based compensation expense, weighted average recognition period (in years)	3 years 55 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option grant period (in years)	10 years
Option exercise price as percentage of fair value of common stock on grate date	100.00%

Number of shares as percentage of common shares outstanding.

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Option exercise price as percentage of fair value of common stock on grate date.

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Stock option granted period.

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Aggregate number of common shares reserved for future issuance.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable within one year (or the operating cycle, if longer).

+ References

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Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable after one year (or the operating cycle, if longer).

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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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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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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- Definition

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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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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