Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Details Textual)

v3.6.0.2
Stock-Based Compensation (Details Textual)
1 Months Ended 12 Months Ended
Dec. 31, 2016
USD ($)
$ / shares
shares
Jun. 01, 2015
shares
Mar. 31, 2012
shares
Dec. 31, 2016
USD ($)
Award
$ / shares
shares
Dec. 31, 2016
GBP (£)
Award
shares
Jan. 02, 2016
USD ($)
$ / shares
shares
Dec. 27, 2014
USD ($)
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Aggregate shares of restricted stock grant       45,000 45,000 70,000 103,000
Total unrecognized compensation | $ $ 1,924,000     $ 1,924,000      
Recognized weighted average period (in years) 8 months 27 days            
Share-based compensation expenses | $       $ 312,000   $ 199,000 $ 173,000
Ratio for additional common stock shares issued, under ESPP       16.67% 16.67%    
2012 Director Equity Plan [Member]              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
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 2,000    
Stock option granted, shares       24,500 24,500 24,375  
Share-based compensation expenses under Director's plan | $       $ 831,000   $ 829,000 677,000
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       33,956 33,956 34,053  
Weighted average price | $ / shares $ 25.95     $ 25.95   $ 29.94  
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 585,384     585,384      
Maximum [Member] | 2012 Director Equity Plan [Member]              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Shares available for issuance 25,000     25,000      
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 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 employees | £         £ 1,500    
Allowable employees purchase rate of common stock based on annual salary       10.00% 10.00%    
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% 110.00%    
Minimum voting stock percentage for incentive stock       10.00% 10.00%    
Number of awards granted under 2006 plan | Award       0 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 10 years    
Equity Incentive Plan (2011 Plan) [Member]              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Shares available for issuance 526,762     526,762      
Aggregate shares of restricted stock grant       1,000,000 1,000,000    
2001 Restricted Stock Plan [Member]              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Restricted stock expense | $       $ 3,676,000   $ 3,254,000 $ 2,961,000
Nonemployee Director Equity and Deferred Compensation Plan [Member]              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]              
Shares available for issuance 174,874     174,874