Represents price per share of shares issued under the Employee Stock Purchase Plan.

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The closing price for entity's stock on the NASDAQ market at end of period.

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The additional 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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The discount rate from market value on specific date that participants pay for shares.

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- Definition

Represents the total fair value of vested stock options.

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- Definition

Represents the total fair value of nonvested equity stock units granted during the period.

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No definition available.

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- Definition

Represents the estimated period of time over which an employee is required to provide service in exchange for the equity-based payment award.

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No definition available.

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Represents the estimated period of time over which a director is required to provide service in exchange for the equity-based payment award.

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No definition available.

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- Definition

Represents the total fair value of options for granted during the period.

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No definition available.

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- Definition

Represents the number of in-the-money stock options exercisable.

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No definition available.

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Represents the number of in-the-money stock options outstanding.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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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

The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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The number of grants made 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

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

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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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Number of additional shares authorized for issuance under an established share-based compensation plan.

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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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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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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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Net 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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Percentage of vesting of share-based compensation awards.

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

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Equity Incentive Plans and Stock-Based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Apr. 23, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate				0.00%
Minimum [Member]
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		0.00%
Maximum [Member]
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		150.00%
Stock Compensation Plan [Member]
Stock-Based Compensation
Shares available for issuance		12,632,940		12,632,940		10,724,228
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	4,000,000	35,400,000		35,400,000
Share Based Compensation Arrangement by Share Based Payment Award Additional Number of Shares Authorized				4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures				362,335
Employee Stock Option [Member]
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number		9,653,633		9,653,633		11,441,646
Entity Closing Stock Price		$ 14.49		$ 14.49
Share Based Compensation Arrangement by Share Based Payment Award Options, In The Money Outstanding, Number		8,001,891		8,001,891
Share Based Compensation Arrangement By Share Based Payment Award, Options in the Money Exercisable, Number		4,302,260		4,302,260
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures			118,615	362,335	1,916,077
Estimated total grant date fair value			$ 0.6	$ 1.7	$ 7.6
Stock-based compensation		$ 2.3	2.4	4.4	4.6
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		9.6		$ 9.6
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				1 year 10 months 28 days
Total fair value of options vested		40.5		$ 40.5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 3.5	1.6	4.6	2.2
Proceeds from Stock Options Exercised				$ 6.0
Employee Stock [Member]
Stock-Based Compensation
Shares available for issuance		2,607,944		2,607,944
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	2,000,000
Share Based Compensation Arrangement by Share Based Payment Award Discount from Market Price Specific Date				15.00%
Stock-based compensation		$ 0.4	$ 1.8	$ 0.8	$ 1.9
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		$ 0.5		$ 0.5
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				4 months
Stock Issued During Period, Shares, Employee Stock Purchase Plans				315,100	374,588
Employee Stock Purchase Plans Price Per Share				$ 9.66	$ 7.42
Restricted Stock and Stock Units [Member]
Stock-Based Compensation
Granted (in shares)		60,724	22,868	1,581,902	228,676
Stock-based compensation		$ 1.7	$ 0.7	$ 2.9	$ 1.3
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		15.5		$ 15.5
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition				3 years 1 day
Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Nonvested Requisite Service Period				4 years
Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options Nonvested Requisite Service Period for Directors				1 year
Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Nonvested Grants in Period Total Fair Value		$ 0.9	$ 0.3	$ 18.0	$ 2.1
Stock Options with Market Condition [Member] \| Employee Stock Option [Member]
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number		1,315,000		1,315,000		1,315,000
Performance Stock Units [Member] \| Restricted Stock and Stock Units [Member]
Stock-Based Compensation
Stock-based compensation		$ 0.3		$ 0.5