Segment Information - Revenue by Major Customer (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2016
Customer A [Domain]
Revenue, Major Customer [Line Items]
Entity-Wide Revenue, Major Customer, Percentage		41.20%
Customer B [Domain]
Revenue, Major Customer [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	40.70%	15.00%
Customer C [Domain]
Revenue, Major Customer [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	12.50%
Accounts Receivable [Member] | Customer B [Domain]
Revenue, Major Customer [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	33.40%		19.10%
Accounts Receivable [Member] | Customer C [Domain]
Revenue, Major Customer [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	15.10%