Other Employee Benefit Plans (Details Textual) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Maximum annual contribution to 401(k) plan by employees, effective January 1, 2015	$ 18,000
Percentage of company matching contribution to 401(K) plan	50.00%
Defined contribution plan employer matching contribution percent	3.00%
Company's contributions to 401(K) plan	$ 900,000	$ 1,100,000	$ 2,900,000
Common stock shares purchase price limit for employees as percentage of market value under Employee Stock Purchase Plan	90.00%
Employee stock purchase plan maximum percentage of purchase employee can make on eligible compensation	10.00%
Maximum number of shares available for purchase by participating employees	2,500,000

Employee stock purchase plan, maximum percentage of purchase an employee can make on eligible compensation.

No definition available.

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Employee stock purchase plan, percentage of purchase price from market value.

No definition available.

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Maximum number of shares made available for purchase by participating employees under employee stock purchase plan.

No definition available.

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Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

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Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

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Percentage employer matches of the employee's percentage contribution matched.

No definition available.

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Maximum amount the employee may contribute to a defined contribution plan.

No definition available.

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