Stock Based Compensation - Summary of Stock Option Plan (Detail)	3 Months Ended
Mar. 31, 2017 $ / shares shares
Shares
Outstanding, Beginning balance (in shares) \| shares	2,431,347
Granted (in shares) \| shares	785,132
Exercised (in shares) \| shares	(33,583)
Canceled/Forfeited (in shares) \| shares	(54,912)
Outstanding, Ending balance (in shares) \| shares	3,127,984
Options exercisable (in shares) \| shares	935,059
Weighted Average Exercise Price Per Share
Outstanding, Beginning balance (usd per share) \| $ / shares	$ 17.09
Granted (usd per share) \| $ / shares	19.03
Exercised (usd per share) \| $ / shares	12.25
Canceled/Forfeited (usd per share) \| $ / shares	17.86
Outstanding, Ending balance (usd per share) \| $ / shares	17.62
Options exercisable (usd per share) \| $ / shares	$ 18.94

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Gross number of share options (or share units) granted during the period.

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

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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

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Number of share options (or share units) exercised during the current period.

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