Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Details Textual)

v3.2.0.727
Stock Based Compensation (Details Textual)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 01, 2015
shares
Mar. 31, 2012
shares
Jun. 27, 2015
USD ($)
Awards
$ / shares
shares
Jun. 28, 2014
USD ($)
Jun. 27, 2015
USD ($)
$ / shares
shares
Jun. 27, 2015
GBP (£)
shares
Jun. 28, 2014
USD ($)
shares
Dec. 27, 2014
$ / shares
Stock Option Plans (Textual) [Abstract]                
Aggregate shares of restricted stock grant     0          
Total unrecognized compensation | $     $ 3,899   $ 3,899      
Recognized weighted average period (in years)     1 year 2 months 45 days          
Ratio for additional common stock shares issued, under ESPP         6 6    
Share based Compensation Expenses | $         $ 124   $ 104  
Director Equity Plan [Member]                
Stock Option Plans (Textual) [Abstract]                
Shares available for issuance     35,000   35,000      
Remaining number of shares to be issued     270,000   270,000      
Stock option granted, shares         10,625 10,625 8,500  
Fee for the chairs of each Board committee 150.00% 125.00%            
Share-based Goods and Nonemployee Services Transaction, Shares Approved for Issuance 2,000              
Common stock shares for each nonemployee director 250 500            
Share based Compensation Expenses under Director's plan | $         $ 409   $ 336  
2006 Stock Option Plan [Member]                
Stock Option Plans (Textual) [Abstract]                
Shares available for issuance     1,125,000   1,125,000      
Exercise price per share not less than fair value percent     110.00%          
Exercise price per share more than voting stock     10.00%          
Number of awards granted under 2006 plan | Awards     0          
2006 Stock Option Plan [Member] | Maximum [Member]                
Stock Option Plans (Textual) [Abstract]                
Stock options maximum term (in years)     10 years          
2001 Restricted Stock Plan [Member]                
Stock Option Plans (Textual) [Abstract]                
Restricted stock expense | $     $ 1,402 $ 1,357        
Equity Incentive Plan (2011 Plan) [Member]                
Stock Option Plans (Textual) [Abstract]                
Aggregate shares of restricted stock grant     1,000,000          
Remaining number of shares to be issued     634,362   634,362      
Employee Stock Purchase Plan [Member]                
Stock Option Plans (Textual) [Abstract]                
Aggregate shares of restricted stock grant         1,096,875 1,096,875    
Rate of common stock at market value         85.00% 85.00%    
Number of shares purchased by employees         16,866 16,866 12,304  
Weighted average price | $ / shares     $ 32.63   $ 32.63     $ 33.35
Employee Stock Purchase Plan [Member] | Minimum [Member]                
Stock Option Plans (Textual) [Abstract]                
Allowable purchase rate of common stock based on annual salary         10.00% 10.00%    
Employee Stock Purchase Plan [Member] | Minimum [Member] | United States [Member]                
Stock Option Plans (Textual) [Abstract]                
Shares allowed to be purchased by U.S. employees and U.K. employees | $         $ 25      
Employee Stock Purchase Plan [Member] | Minimum [Member] | United Kingdom [Member]                
Stock Option Plans (Textual) [Abstract]                
Shares allowed to be purchased by U.S. employees and U.K. employees | £           £ 1,500    
Employee Stock Purchase Plan and U.K. Plan [Member]                
Stock Option Plans (Textual) [Abstract]                
Remaining number of shares to be issued     636,527   636,527      
Nonemployee Director Equity and Deferred Compensation Plan [Member]                
Stock Option Plans (Textual) [Abstract]                
Shares available for issuance     212,124   212,124