Warrants (Details) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2019 USD ($)	Sep. 28, 2018 USD ($)	Sep. 27, 2019 USD ($)	Sep. 28, 2018 USD ($)	Jul. 08, 2019 USD ($)	Jul. 01, 2019 shares	Jun. 28, 2019 USD ($)	Dec. 31, 2018 Measurement_Input	Sep. 26, 2016 $ / shares shares
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares									$ 4.76
Reduction to net revenues - amortization of the Warrant			$ 13,137	$ 1,185
Comcast Milestones Achievement [Member]
Class of Warrant or Right [Line Items]
Right to purchase shares vested | shares						1,954,042
Warrants and Rights Outstanding	$ 19,600		19,600				$ 3,500
Comcast CableOS Software License Agreement [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding					$ 16,100
Measurement Input, Risk Free Interest Rate [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input | Measurement_Input								0.019
Measurement Input, Option Volatility [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input | Measurement_Input								0.486
Measurement Input, Expected Term [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Term								4 years 2 months 12 days
Measurement Input, Expected Dividend Rate [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input | Measurement_Input								0
Maximum [Member] | Comcast Warrant Expires September 26, 2023 [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares									7,816,162
Revenue from Contract with Customer Benchmark [Member]
Class of Warrant or Right [Line Items]
Reduction to net revenues - amortization of the Warrant	$ 13,100	$ 800	$ 13,100	$ 1,200