Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details Textual)

v3.21.2
Stock-Based Compensation (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
9 Months Ended
Oct. 02, 2021
Sep. 26, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Recognized weighted average period (in years) 2 years 2 months 12 days  
Contractual term of stock options 10 years  
Unrecognized compensation cost related to the stock options $ 357  
Award of shares granted (in shares) 102,000  
Stock-based compensation expense $ 6,233 $ 3,830
2012 Nonemployee Director Fees Plan [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Award of shares granted (in shares) 20,375 11,775
Stock-based compensation expense $ 1,586 $ 480
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]    
Number of shares purchased by employees 22,747 33,519
Weighted average price $ 57.93 $ 30.65
Share-based compensation expenses $ 431 $ 220
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 $ 4,168 $ 3,158
Total unrecognized compensation $ 7,131  
Recognized weighted average period (in years) 1 year 9 months 18 days