Stock-Based Compensation - Summary of ESPP Share Activity (Detail) - shares	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchases	(58,734)	(44,161)
Available for future purchases, March 31, 2020	2,479,875
2019 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional shares reserved	86,093
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Available for future purchases, January 1, 2020	438,434
Purchases	(58,734)
Available for future purchases, March 31, 2020	465,793
Employee Stock Purchase Plan [Member] \| 2019 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional shares reserved	86,093

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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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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Number of shares issued during the period as a result of an employee stock purchase plan.

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