v3.19.2

Employee Stock Purchase Plan - Additional Information (Detail) - shares	Jun. 20, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding		6,771,807		3,351,132
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding		0		0
Common Stock [Member] | Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares available for issuance	300,000
Maximum number of shares provided for issuance	350,000		350,000
Percentage of annual increase in number of shares reserved for issuance	1.00%

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Aggregate number of common shares reserved for future issuance.

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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 options outstanding, including both vested and non-vested options.

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