Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Details Textual)

v3.22.0.1
Stock-Based Compensation (Details Textual)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Feb. 28, 2015
shares
Jan. 01, 2022
USD ($)
shares
$ / shares
Jan. 01, 2022
GBP (£)
shares
Jan. 02, 2021
USD ($)
$ / shares
shares
Dec. 28, 2019
USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Stock option granted, shares | shares   108,000 108,000    
Stock-based compensation expense   $ 8,880   $ 5,781 $ 5,207
Employee Stock Purchase Plan [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Rate of common stock at market value   85.00% 85.00%    
Employee Stock Purchase Plan [Member] | Maximum [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Aggregate number of shares authorized for grant | shares   1,096,875      
Employee Stock Purchase Plan [Member] | United States [Member] | Maximum [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Shares allowed to be purchased by employees   $ 25      
Employee Stock Purchase Plan [Member] | United Kingdom [Member] | Maximum [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%    
Employee Stock Purchase Plan and U.K. Plan [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Shares available for issuance | shares   382,209      
Number of shares purchased by employees | shares   29,420 29,420 43,574  
Weighted average price | $ / shares   $ 60.71   $ 30.86  
Share-based compensation expenses   $ 659   $ 431 551
Ratio for additional common stock shares issued, under ESPP | shares   6 6    
Time Based [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Vesting period   3 years 3 years    
Performance Based [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Vesting period   3 years 3 years    
RSUs [Member] | Minimum [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Target amount percentage   0.00% 0.00%    
RSUs [Member] | Maximum [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Target amount percentage   200.00% 200.00%    
Restricted Stock and Restricted Stock Units [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Compensation expense   $ 5,954   4,182 3,465
Fair value of RSUs/restricted stock granted   6,212   $ 6,843 5,079
Total unrecognized compensation   $ 6,132      
Recognized weighted average period (in years)   1 year 6 months 1 year 6 months    
Stock Options [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Contractual term of stock options   10 years 10 years    
Unrecognized compensation cost related to the stock options   $ 270      
Recognized weighted average period (in years)   1 year 10 months 24 days 1 year 10 months 24 days    
Exercise prices per share, lower range limit | $ / shares   $ 35.04      
Exercise prices per share, upper range limit | $ / shares   $ 55.30      
Unvested stock options | shares   23,063      
Vested unexercised stock options | shares   3,673 3,673    
2019 Plan [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Shares available for issuance | shares   909,260      
Stock-based compensation expense   $ 39      
2019 Plan [Member] | Restricted Stock and Restricted Stock Units [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Stock-based compensation expense   27      
2019 Plan [Member] | Audit [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Stock-based compensation expense   5      
2019 Plan [Member] | ESG [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Stock-based compensation expense   $ 3      
2012 Non-Employee Director Fees Plan [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Common stock shares for each nonemployee director | shares 2,000        
Fee for the chairs of each Board committee 150.00%        
Annual retainer of common stock received by non employee directors | shares 250        
Stock option granted, shares | shares   26,500 26,500 26,675  
Stock-based compensation expense   $ 2,202   $ 1,178 $ 1,162
Director Compensation Policy Member | Board [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Cash award   $ 22