Summary of Significant Accounting Policies - Concentration of Foreign Sales Risk (Details)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Geographic Concentration Risk \| Sales Revenue, Net \| Non-US
Concentration Risk [Line Items]
International sales comprised of total net revenue	75.00%	76.00%	78.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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