Share based compensation arrangement, annual increase in number of common shares reserved for future issuance.

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- Definition

Share based compensation arrangement by share based payment award consecutive overlapping offering period.

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- Definition

Share based compensation arrangement by share based payment award first offering period commence date.

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- Definition

Share based compensation arrangement, percentage of annual increase in shares reserved for issuance as a percentage of outstanding shares of common stock.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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- Definition

Aggregate number of common shares reserved for future issuance.

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- Definition

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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- Definition

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

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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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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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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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

Number of additional shares authorized for issuance under share-based payment arrangement.

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- Definition

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

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- Definition

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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- Definition

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

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Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Tax benefits for stock-based compensation expense recognized		$ 0	$ 0	$ 0	$ 0
Stock options granted				83,000
Total unrecognized stock-based compensation expense relating to unvested stock options		36,600,000		$ 36,600,000
Total stock-based compensation expense		$ 7,762,000	$ 3,105,000	$ 15,251,000	$ 5,939,000
Performance-Based Vesting
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted		0	0	0	0
Market-Based Vesting
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted		0	0	0	0
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average recognition period				2 years 6 months
Unvested Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average recognition period				3 years 4 months 24 days
Weighted-average fair value of RSUs granted				$ 66.77
Number of RSUs granted				43,000	0
Total unrecognized stock-based compensation expense		$ 45,300,000		$ 45,300,000
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance	500,000
Increase in number of common stock shares reserved for issuance per year	1,000,000
Percentage increase in shares reserved for issuance per year	1.00%
Price as a percentage of fair market value of common stock	85.00%
Consecutive overlapping offering period	24 months
First offering period commence date				Jul. 18, 2018
Total stock-based compensation expense		$ 200,000	$ 200,000	$ 400,000	$ 300,000
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance	4,000,000
Increase in number of common stock shares reserved for issuance per year	5,000,000
Percentage increase in shares reserved for issuance per year	5.00%
Maximum number of additional shares authorized to be added to the Plan				5,098,992
2012 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	4 years
2012 Equity Incentive Plan \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option expiration period	10 years