Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Dec. 31, 2018	Sep. 26, 2016
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights						7,816,162
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 4.76
Fair Value Adjustment of Warrants	$ 284		$ 395
Comcast Product Supply Agreement [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding						781,617
Fair Value Assumptions, Expected Dividend Rate			0.00%
Comcast Milestones Achievement [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Unissued						1,954,042
Comcast Exceeding Specified Cumulative Purchase Volume [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Unissued						1,172,425
Sales Revenue, Goods, Net [Member] | Comcast Product Supply Agreement [Member]
Class of Warrant or Right [Line Items]
Fair Value Adjustment of Warrants	300	$ 0	$ 400	$ 400
Prepaid Expenses and Other Current Assets [Member]
Class of Warrant or Right [Line Items]
Prepaid Warrants Incentive	$ 600		$ 600
Scenario, Forecast [Member] | Prepaid Expenses and Other Current Assets [Member]
Class of Warrant or Right [Line Items]
Prepaid Warrants Incentive					$ 1,000