Patents Cost and Accumulated Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Patents [Line Items]
Capitalized patent costs	$ 117,970	$ 0
Accumulated amortization / impairment charges	$ 109,663	$ 0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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