Quarterly report pursuant to Section 13 or 15(d)

Revenues (Details)

v3.8.0.1
Revenues (Details) - USD ($)
$ in Thousands
Mar. 29, 2018
Dec. 29, 2017
Dec. 28, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Retained Earnings (Accumulated Deficit) $ 159,247   $ 119,550
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Retained Earnings (Accumulated Deficit)   $ 7,800