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Share-based Compensation Arrangement by Share-based Payment Award, Annual Increase In Shares Reserved As Percentage Of Prior Year Shares Outstanding

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Share-Based Compensation Arrangement By Share-Based Payment Award, Annual Increase In Shares Reserved, Maximum Shares

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Share-Based Compensation Arrangement By Share-Based Payment Award, Expiration Period For Individual Owning More Than 10% Of Outstanding Shares

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Share-Based Compensation Arrangement By Share-Based Payment Award, Offering Period Interval

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Share-based Compensation Arrangement by Share-based Payment Award, Options, Early Exercise, Common Stock Subject To Repurchase

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Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Exercise Price As Percent Of Fair Market Value

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Share-based Compensation Arrangement by Share-based Payment Award, Option, Exercise Price As Percent Of Fair Market Value For Individual Owning More Than 10% Of Outstanding Shares

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

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Aggregate number of common shares reserved for future issuance.

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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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Amount of obligations incurred for employer-related costs classified as other, payable within one year or the normal operating cycle, if longer.

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

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

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Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	12 Months Ended
	Jan. 01, 2020	Mar. 22, 2019	Jan. 01, 2019	Oct. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of options exercised					$ 6,800	$ 3,600
Weighted-average grant date fair value of options granted (in dollars per share)					$ 9.78	$ 3.98
Unrecognized compensation costs					$ 5,500
Early exercise of stock options, share subject to repurchase (in shares)					21,404	74,019
Liability for early exercise of unvested stock options					$ 97	$ 331
Stock-based compensation expense					$ 7,464	2,312
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of option as percent of fair market value when individual owns more than 10% of shares outstanding (percent)					110.00%
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option term (in years)					10 years
Stock option term when grantee holds more than 10% of shares outstanding (in years)					5 years
Award vesting period (in years)					4 years
Unrecognized compensation cost, expected period for recognition (in years)					2 years 7 months 6 days
Incentive Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of option as percent of fair market value (percent)					100.00%
Nonqualified Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of option as percent of fair market value (percent)					85.00%
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, expected period for recognition (in years)					3 years 1 month 6 days
Unrecognized compensation cost					$ 8,600
Restricted Stock Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)					2 years
Restricted Stock Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)					4 years
2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in shares reserved as percentage of prior year-end shares outstanding (percent)					5.00%
Increase in number of shares reserved for future issuance (in shares)			1,222,538
Shares available for future grants (in shares)					2,567,295
2018 Equity Incentive Plan \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares reserved for future issuance (in shares)	1,258,190
2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in shares reserved as percentage of prior year-end shares outstanding (percent)					1.00%
Annual increase in shares reserved, maximum (in shares)					555,555
Increase in number of shares reserved for future issuance (in shares)		244,507
Unrecognized compensation cost					$ 300
Purchase price of common stock as a percent of fair market value (percent)				85.00%
Employees stock purchase program offering period interval (in months)				6 months
Number of shares reserved for issuance (in shares)				515,307	591,357
Accrued compensation and related expenses for employee payroll deductions					$ 200	400
Stock-based compensation expense					$ 800	$ 200
2018 Employee Stock Purchase Plan \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares reserved for future issuance (in shares)	251,638