Basis of Presentation and New Accounting Standards New Accounting Standard (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jun. 25, 2018	Jun. 24, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ (713,780)		$ (482,710)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit		$ 10,299
Revenues	$ 1,600
Retained Earnings [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit		$ 10,299