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Stock Based Compensation (Details Textual)
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3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 9 Months Ended | 9 Months Ended | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Sep. 27, 2014
USD ($)
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Sep. 27, 2014
USD ($)
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Sep. 28, 2013
USD ($)
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Sep. 27, 2014
Director Equity Plan [Member]
USD ($)
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Sep. 28, 2013
Director Equity Plan [Member]
USD ($)
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Sep. 27, 2014
2006 Stock Option Plan [Member]
Awards
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Sep. 27, 2014
2006 Stock Option Plan [Member]
Maximum [Member]
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Sep. 27, 2014
2001 Restricted Stock Plan [Member]
USD ($)
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Jun. 30, 2012
2001 Restricted Stock Plan [Member]
USD ($)
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Sep. 27, 2014
Equity Incentive Plan (2011 Plan) [Member]
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Sep. 27, 2014
Employee Stock Purchase Plan [Member]
USD ($)
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Sep. 28, 2013
Employee Stock Purchase Plan [Member]
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Jun. 30, 2012
Employee Stock Purchase Plan [Member]
USD ($)
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Sep. 27, 2014
Employee Stock Purchase Plan [Member]
Minimum [Member]
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Sep. 27, 2014
Employee Stock Purchase Plan [Member]
Minimum [Member]
United States [Member]
USD ($)
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Sep. 27, 2014
Employee Stock Purchase Plan [Member]
Minimum [Member]
United Kingdom [Member]
GBP (£)
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Sep. 27, 2014
Employee Stock Purchase Plan and U.K. Plan [Member]
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Sep. 27, 2014
Nonemployee Director Equity and Deferred Compensation Plan [Member]
USD ($)
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| Stock Option Plans (Textual) [Abstract] | ||||||||||||||||||
| Shares available for issuance | 25,000 | 1,125,000 | 928,125 | 227,249 | ||||||||||||||
| Exercise price per share not less than fair value percent | 110.00% | |||||||||||||||||
| Exercise price per share more than voting stock | 10.00% | |||||||||||||||||
| Stock options maximum term (in years) | 10 years | |||||||||||||||||
| Number of awards granted under 2006 plan | 0 | |||||||||||||||||
| Minimum period before shares become non-forfeitable (in months) | 6 months | |||||||||||||||||
| Plan Expiration year | 2011 | |||||||||||||||||
| Aggregate shares of restricted stock grant | 0 | 1,000,000 | 1,096,875 | |||||||||||||||
| Remaining number of shares to be issued | 270,000 | 732,062 | 660,258 | |||||||||||||||
| Restricted stock expense | $ 2,021,000 | $ 1,557,000 | ||||||||||||||||
| Total unrecognized compensation | 2,718,000 | 2,718,000 | ||||||||||||||||
| Recognized weighted average period (in years) | 0 years 10 months 30 days | |||||||||||||||||
| Rate of common stock at market value | 85.00% | |||||||||||||||||
| Ratio for additional common stock shares issued, under ESPP | 6 | |||||||||||||||||
| Shares allowed to be purchased by U.S. employees and U.K. employees | 25,000 | 1,500 | ||||||||||||||||
| Allowable purchase rate of common stock based on annual salary | 10.00% | |||||||||||||||||
| Number of shares purchased by employees | 18,373 | 27,060 | ||||||||||||||||
| Weighted average price | $ 33.92 | $ 24.05 | ||||||||||||||||
| Share based Compensation Expenses | 138,000 | 142,000 | ||||||||||||||||
| Stock option granted, shares | 13,000 | 12,500 | 375 | |||||||||||||||
| Cash fees paid | 3,000 | |||||||||||||||||
| Fee for the chairs of each Board committee | 125.00% | 25.00% | ||||||||||||||||
| Deferred stock units outstanding | 0 | 0 | ||||||||||||||||
| Common stock shares for each nonemployee director | 500 | |||||||||||||||||
| Share based Compensation Expenses under Director's plan | $ 514,000 | $ 432,000 | ||||||||||||||||