Stock-Based Compensation - Additional Information (Detail)	12 Months Ended
Dec. 31, 2018 shares
2006 Plan and 2016 Plan \| Outstanding options and RSUs granted (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares subject to outstanding options and RSUs (in shares)	5,682,618
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance (in shares)	7,100,000
Number of shares of common stock available for future grant (in shares)	4,576,126

Aggregate number of common shares reserved for future issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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.

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Number of options outstanding, including vested and non-vested options, as of the balance sheet, plus the number of non-vested restricted stock units outstanding as of the balance sheet date.

+ References

No definition available.

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