Stock Plans and Stock-Based Compensation - Schedule of Vested and Nonvested Stock Option Activity (Details) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, Vested	515,735	748,148
Weighted average exercise price, Vested	$ 13.51	$ 10.39
Options outstanding, Nonvested	1,320,936	1,692,142
Weighted average exercise price, Nonvested	$ 25.65	$ 19.27

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- Definition

Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ 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
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ References

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- Definition

Number of non-vested options outstanding.

+ References

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- Definition

Weighted average grant-date fair value of non-vested options outstanding.

+ References

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