Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details)

v3.19.3
Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
May 17, 2018
Sep. 26, 2019
Mar. 28, 2019
Sep. 26, 2019
Dec. 27, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares issued under employee stock plan   $ 1,026 $ 1,419    
Stock purchase plan, expense   $ 130   $ 400  
Class A Common Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Common stock, par value   $ 0.001   $ 0.001 $ 0.001
Employee Stock Purchase Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Fair market value measurement period 6 months        
Employee Stock Purchase Plan [Member] | Minimum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Purchase price, as a percentage of fair market value 85.00%        
Employee Stock Purchase Plan [Member] | Class A Common Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares of stock authorized under the plan 1,500,000        
Common stock, par value $ 0.001