Stock Based Awards and Other Equity Instruments - Summary of RSU Activity on Common Stock (Details) (Restricted Stock Units (RSUs), USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2014
Restricted Stock Units (RSUs)
RSUs outstanding
Unvested RSUs outstanding, Beginning balance	1,135
Unvested RSUs, Granted	460
Unvested RSUs, Vested and released	(227)
Unvested RSUs, Cancelled	(36)
Unvested RSUs outstanding, Ending balance	1,332
Weighted Average Grant-Date Fair Value Per Share
Unvested RSUs outstanding, Weighted Average Grant-Date Fair Value Per Share, Beginning balance	$ 49.64
Weighted Average Grant-Date Fair Value Per Share, Granted	$ 96.34
Weighted Average Grant-Date Fair Value Per Share, Vested and released	$ 43.61
Weighted Average Grant-Date Fair Value Per Share, Cancelled	$ 61.68
Unvested RSUs outstanding, Weighted Average Grant-Date Fair Value Per Share, Ending balance	$ 66.46
Aggregate Intrinsic Value
Unvested RSUs outstanding, Aggregate Intrinsic Value	$ 121

Stock Based Awards and Other Equity Instruments - Summary of RSU Activity on Common Stock (Details) (Restricted Stock Units (RSUs), USD $)
In Thousands, except Per Share data, unless otherwise specified

3 Months Ended

Mar. 31, 2014

Restricted Stock Units (RSUs)

RSUs outstanding

Unvested RSUs outstanding, Beginning balance

1,135

Unvested RSUs, Granted

460

Unvested RSUs, Vested and released

(227)

Unvested RSUs, Cancelled

(36)

Unvested RSUs outstanding, Ending balance

1,332

Weighted Average Grant-Date Fair Value Per Share

Unvested RSUs outstanding, Weighted Average Grant-Date Fair Value Per Share, Beginning balance

$ 49.64

Weighted Average Grant-Date Fair Value Per Share, Granted

$ 96.34

Weighted Average Grant-Date Fair Value Per Share, Vested and released

$ 43.61

Weighted Average Grant-Date Fair Value Per Share, Cancelled

$ 61.68

Unvested RSUs outstanding, Weighted Average Grant-Date Fair Value Per Share, Ending balance

$ 66.46

Aggregate Intrinsic Value

Unvested RSUs outstanding, Aggregate Intrinsic Value

$ 121

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Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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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).

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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).

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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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-Publisher FASB

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-SubTopic 10

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-Subparagraph (c)(2)(i)-(ii)

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Name Accounting Standards Codification

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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-Subparagraph (c)(2)(iii)(2)

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