Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details Textual)

v3.5.0.2
Stock-Based Compensation (Details Textual)
1 Months Ended 3 Months Ended 9 Months Ended
Jun. 01, 2015
shares
Mar. 31, 2012
shares
Oct. 01, 2016
USD ($)
Award
$ / shares
shares
Oct. 01, 2016
USD ($)
$ / shares
shares
Oct. 01, 2016
GBP (£)
shares
Sep. 26, 2015
USD ($)
$ / shares
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Aggregate shares of restricted stock grant       45,000 45,000  
Total unrecognized compensation | $     $ 2,655,000 $ 2,655,000    
Recognized weighted average period (in years)       11 months 27 days 11 months 27 days  
Share-based compensation expenses | $       $ 221,000   $ 159,000
Ratio for additional common stock shares issued, under ESPP       600.00% 600.00%  
Director Equity Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares available for issuance     35,000 35,000    
Remaining number of shares to be issued     270,000 270,000    
Common stock shares for each nonemployee director 250 500        
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          
Stock option granted, shares       18,625 18,625 17,500
Share-based compensation expenses under Director's plan | $       $ 588,000   $ 617,000
Employee Stock Purchase Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
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       26,575 26,575 23,607
Weighted average price | $ / shares     $ 25.99 $ 25.99   $ 32.71
Employee Stock Purchase Plan and U.K. Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Remaining number of shares to be issued     592,765 592,765    
Minimum [Member] | Employee Stock Purchase Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Allowable purchase rate of common stock based on annual salary       10.00% 10.00%  
Minimum [Member] | Employee Stock Purchase Plan [Member] | United States [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares allowed to be purchased by U.S. employees and U.K. employees | $       $ 25,000    
Minimum [Member] | Employee Stock Purchase Plan [Member] | United Kingdom [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares allowed to be purchased by U.S. employees and U.K. employees | £         £ 1,500  
2006 Stock Option Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares available for issuance     1,125,000 1,125,000    
Exercise price per share not less than fair value percent     110.00%      
Minimum voting stock percentage for incentive stock     10.00%      
Number of awards granted under 2006 plan | Award     0      
2006 Stock Option Plan [Member] | Maximum [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Stock options maximum term (in years)     10 years      
Equity Incentive Plan (2011 Plan) [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Aggregate shares of restricted stock grant     1,000,000      
Remaining number of shares to be issued     522,212 522,212    
2001 Restricted Stock Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Restricted stock expense | $       $ 3,051,000   $ 2,159,000
Nonemployee Director Equity and Deferred Compensation Plan [Member]            
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]            
Shares available for issuance     180,749 180,749