The maximum amount allowed for advance payroll deductions in a calendar year for employee stock purchase plan.

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- Definition

Share Based Compensation Arrangement by Share Based Payment Award Contractual Term Range

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- Definition

Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Annual Forfeiture Rate

+ References

No definition available.

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- Definition

Share Based Compensation Arrangement By Share Based Payment Award Grant Date Fair Value Of Awards

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No definition available.

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- Definition

Share Based Compensation Arrangement by Share based Payment Award, Vesting Percentage

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No definition available.

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- Definition

Share Based Compensation Arrangements By Share Based Payment Award Percentage Of Market Price At Eligible Employees Granted Options To Purchase Shares

+ 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.

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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.

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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- Definition

Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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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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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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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.

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No definition available.

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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.

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Share-Based Compensation - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of average closing price to be paid by employees			85.00%
Maximum common stock purchases through advance payroll deductions in a calendar year			$ 25,000
Share-based compensation	$ 894,000	$ 823,000	$ 2,546,000	$ 1,884,000
Forfeiture rate			2.20%
Unrecognized compensation expense related to stock options	$ 0		$ 0
Aggregate intrinsic value of stock options exercised			1,203,000	1,675,000
Cash receipts of stock options exercised			$ 1,093,000	$ 2,323,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option term			10 years
Stock options vesting percentage			100.00%
Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period			6 months
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period			2 years
RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period			3 years
Outstanding DSUs (in shares)	359,736		359,736		366,993
Unrecognized compensation expense related to RSAs	$ 8,480,000		$ 8,480,000
Unrecognized compensation expense expected recognition period			1 year 8 months 4 days
DSUs \| Non-employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding DSUs (in shares)	0		0
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to stock options	$ 0		$ 0
Grant date fair value of ESPP options	$ 39,424