Represents the number of different vesting criteria of RSU's issued by the entity.

No definition available.

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Represents the number of shares included in the authorized shares which was previously reserved for issuance under the plan.

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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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Unrecognized cost of unvested share-based compensation awards.

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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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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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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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- References

No definition available.

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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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- Definition

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

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No definition available.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

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

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- Definition

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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No definition available.

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- Definition

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

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No definition available.

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- Definition

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

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No definition available.

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- Definition

Percentage of vesting of share-based compensation awards.

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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.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

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Stock-based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	May 07, 2014 shares	Jun. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) item $ / shares shares	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares
Stock-based Compensation
Unrecognized compensation cost		$ 27,200		$ 27,200
Equity Incentive Plan 2010
Stock-based Compensation
Number of shares authorized \| shares		5,608,176		5,608,176
Shares included in the authorized shares which was previously reserved for issuance \| shares		608,176		608,176
Shares
Granted (in shares) \| shares	0
Employee and Directors Stock Options
Stock-based Compensation
Term of award				10 years
Vesting period				3 years
Stock-based compensation		$ 0	$ 0	$ 0	$ 0
Unrecognized compensation cost		$ 0		$ 0
Shares
Balance at the beginning of the period (in shares) \| shares				2,858,158
Exercised (in shares) \| shares				(206,363)
Balance at the end of the period (in shares) \| shares		2,651,795		2,651,795		2,858,158
Vested and exercisable at the end of the period (in shares) \| shares		2,651,795		2,651,795
Exercise Price
Balance at the beginning of the period (in dollars per share) \| $ / shares				$ 20.37
Exercised (in dollars per share) \| $ / shares				20.00
Balance at the end of the period (in dollars per share) \| $ / shares		$ 20.40		20.40		$ 20.37
Vested and exercisable at the end of the period (in dollars per share) \| $ / shares		$ 20.40		$ 20.40
Remaining Contractual Term
Remaining Contractual Term (in years)				1 year 11 months 27 days		2 years 5 months 27 days
Vested and exercisable				1 year 11 months 27 days
Aggregate Intrinsic Value
Balance at the beginning of the period				$ 79,230
Exercised				4,903
Balance at the end of the period		$ 57,204		57,204		$ 79,230
Vested and exercisable at the end of the period		57,204		$ 57,204
Restricted Stock Units
Stock-based Compensation
Number of different vesting criteria \| item				4
Stock-based compensation		$ 4,900	$ 5,300	$ 8,300	$ 9,100
Restricted Stock Units \| Vesting Tranche One
Stock-based Compensation
Vesting period				3 years
Restricted Stock Units \| Vesting Tranche Three
Stock-based Compensation
Vesting period				3 years
Restricted Stock Units \| Vesting Tranche Four
Stock-based Compensation
Vesting period				3 years
Restricted Stock Units \| Minimum \| Vesting Tranche Two
Stock-based Compensation
Vesting period				1 year
Restricted Stock Units \| Maximum \| Vesting Tranche Two
Stock-based Compensation
Vesting period				2 years
Restricted Stock With Total Shareholder Return Conditions \| Minimum
Stock-based Compensation
Percentage of shares vested				0.00%
Restricted Stock With Total Shareholder Return Conditions \| Maximum
Stock-based Compensation
Percentage of shares vested				200.00%