Stockholders' Equity - Summary of Weighted Average Assumptions Used to Estimate Fair Value of Stock Option (Detail) - Stock Options [Member] - $ / shares	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected option term (in years)	6 years 3 months 18 days	6 years 3 months 18 days
Risk-free interest rate	2.20%	2.20%
Expected volatility	40.00%	40.00%
Weighted average exercise price	$ 18.60	$ 18.60
Weighted average fair value at grant date	$ 8.06	$ 8.06

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

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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.

+ References

No definition available.

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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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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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