Share-based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued upon the exercise of stock options	1,489,067	1,611,731
Share-based compensation expense	$ 7,302	$ 4,876
Shares issued under the ESPP	203,061	282,101
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period of stock options granted	10 years
Weighted-average fair value of stock option awards granted (per share)	$ 3.56	$ 1.56
Intrinsic value of stock options exercised during period	$ 5,600	$ 2,400
Unrecognized share-based compensation expense related to non-vested stock options	$ 9,000
Expected recognition period	2 years 9 months 18 days
Share-based compensation expense	$ 3,500	2,500
Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period	10 months 24 days
Share-based compensation expense	$ 3,500	$ 2,200
Weighted-average grant-date fair value of RSUs granted (per share)	$ 5.07	$ 2.01
Total vest date fair value of RSUs vested	$ 4,000	$ 2,100
Unrecognized share-based compensation expense related to non-vested RSUs	$ 600
Restricted Stock Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Restricted Stock Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan	5,324,000
Share-based compensation expense	$ 300	$ 200
Percentage of lower limit value of common stock	85.00%
Purchase period duration	6 months
Maximum limit of payroll deductions (percent)	10.00%
2015 Incentive Compensation Plan \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan	1,946,915
2018 Omnibus Incentive Compensation Plan \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan	20,576,085

Share-based Compensation Arrangement by Share-based Payment Award, Purchase Period

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

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Commitment made to pay deferred cash remuneration expressed as a percentage of the individual's base salary.

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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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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 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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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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 shares authorized for issuance under share-based payment arrangement.

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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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