Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Details Textual)

v3.24.0.1
Stock-Based Compensation (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
Feb. 28, 2015
Dec. 30, 2023
Dec. 31, 2022
Jan. 01, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Contractual term of stock options   10 years    
Stock option granted, shares   237,000    
Stock-based compensation expense   $ 11,600 $ 8,600 $ 8,900
Monte Carlo Valuation Model [Member] | Minimum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period   1 year    
Monte Carlo Valuation Model [Member] | Maximum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period   2 years    
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%    
Employee Stock Purchase Plan and U.K. Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares available for issuance   300,233    
Number of shares purchased by employees   43,585 38,392 29,420
Weighted average price   $ 46.52 $ 51.54 $ 60.71
Share-based compensation expenses   $ 500 $ 400 $ 700
Ratio for additional common stock shares issued, under ESPP   6    
Time Based [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period   3 years    
Performance Based [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period   3 years    
RSUs [Member] | Minimum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Target amount percentage   0.00%    
RSUs [Member] | Maximum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Target amount percentage   200.00%    
Restricted Stock and Restricted Stock Units [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Compensation expense   $ 8,400 7,000 6,000
Fair value of RSUs/restricted stock granted   13,300 $ 9,700 6,200
Total unrecognized compensation   $ 8,800    
Recognized weighted average period (in years)   1 year 8 months 12 days    
Employee Stock Option        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Unrecognized compensation cost related to the stock options   $ 100    
Recognized weighted average period (in years)   8 months 12 days    
Unvested stock options   45,334    
Vested unexercised stock options   0    
Exercise price per share   $ 50.6    
Employee Stock Option | Monte Carlo Valuation Model [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Contractual term of stock options   10 years    
Options grant date fair value   $ 2,300    
Unvested stock options   68,000    
Vested unexercised stock options   0    
Exercise price per share   $ 50.6    
Employee Stock Option | Black Scholes Valuation Model [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period   3 years    
Contractual term of stock options   10 years    
Exercise prices per share, lower range limit   $ 35.04    
Exercise prices per share, upper range limit   $ 55.03    
Unvested stock options   4,999    
Vested unexercised stock options   19,234    
2019 Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares available for issuance   978,469    
Stock option granted, shares   20,564 18,260  
Stock-based compensation expense   $ 1,300 $ 500  
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 2,000      
Fee for the chairs of each Board committee 150.00%      
Annual retainer of common stock received by non employee directors 250      
Stock option granted, shares   26,500    
Stock-based compensation expense       $ 2,200
Two Thousand And Twenty Three Equity Incentive Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares available for issuance   1,000,000