Warrants (Detail Textuals) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) Agreement shares
Class of Warrant or Right [Line Items]
Number of warrant and registration rights agreements | Agreement			2
Warrants vested and outstanding	2.2	2.2
Warrants exercise price | $ / shares	$ 24.64	$ 24.64
Charter and Comcast
Class of Warrant or Right [Line Items]
Reduction to net sales in connection with warrants | $	$ 0	$ 0	$ 30,200
Warrants | Maximum
Class of Warrant or Right [Line Items]
Aggregate number of shares purchase			14.0