Summary of Significant Accounting Policies Concentration of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk
Disclosure On Geographic Areas Revenue From External Customers Attributed to France	99.00%	99.00%	94.00%
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Entity's Country of Domicile, Percent	1.00%	1.00%	6.00%