Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Employee Stock Purchase Plan (Details)

v3.10.0.1
Stockholders' Equity - Employee Stock Purchase Plan (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
May 17, 2018
Dec. 27, 2018
Dec. 28, 2017
May 02, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock, par value       $ 0.001
Class A Common Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock, par value   $ 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      
Stock purchase plan, employee contributions   $ 1,400    
Stock purchase plan, expense   $ 333    
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