Offering period of employee stock purchase plan.

No definition available.

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- Definition

Reduction in number of shares available for grant.

+ References

No definition available.

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- Definition

Share based compensation arrangement by share based payment award purchase price description percentage.

+ References

No definition available.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Required Number of Minimum Weekly Hours of Employed

+ References

No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Publisher FASB
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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (c)(2)(iii)(1)
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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

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 maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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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.

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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- Definition

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

+ References

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-Publisher FASB
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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Stock Plans and Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vests over a requisite service period		3 years
Fair value of options vested		$ 6,700	$ 6,100	$ 4,800
Aggregate intrinsic value of options exercised		$ 15,300	$ 5,600	$ 10,400
Shares, granted (in shares)		675,358
Shares issued under employee stock purchase plan (in shares)		36,253	37,531	50,343
Share-based compensation expense		$ 11,537	$ 10,117	$ 12,598
Unrecognized stock compensation cost		$ 20,200
Weighted average period		2 years 8 months 12 days
Options to Purchase Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value of options granted (in dollars per share)		$ 9.92	$ 5.89	$ 6.16
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value of restricted stock granted (in dollars per share)		$ 25.10	$ 16.33	$ 16.71
Total fair value of restricted stock		$ 4,800	$ 5,100	$ 5,500
2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option expiration period		10 years
Reduction in number of shares available for grant (in shares)		1.62
Number of shares authorized for grant (in shares)		5,600,000.0
Share available for grant (in shares)		7,800,000
2014 Omnibus Incentive Plan \| Restricted Stock Units (RSUs) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
2014 Omnibus Incentive Plan \| Restricted Stock Units (RSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
2014 Omnibus Incentive Plan \| Options to Purchase Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
2014 Omnibus Incentive Plan \| Options to Purchase Common Stock \| Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Employee Stock Purchase Plan 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vests over a requisite service period		3 months
Number of shares authorized for grant (in shares)		850,000
Share available for grant (in shares)		200,000
Offering period		6 months
Number of minimum weekly hours of employment		20 hours
Price at which employee can purchase common stock in an offering percentage		95.00%
Weighted-average fair value of restricted stock granted (in dollars per share)		$ 4.06	$ 4.07	$ 1.74
Share-based compensation expense		$ 100	$ 200	$ 100
2017 Performance Awards \| Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Shares, granted (in shares)	231,384
Weighted-average fair value of restricted stock granted (in dollars per share)	$ 23.14