Inventories (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Inventory, Net [Abstract]
Raw materials	$ 24,535		$ 24,535		$ 23,269
Finished goods	2,712		2,712		4,012
Inventory, Gross	27,247		27,247		27,281
Less: inventory valuation allowance	(23,434)		(23,434)		(23,016)
Inventories, net	3,813		$ 3,813		$ 4,265
Age of consignment inventory purchased as a result of forecasted demand			180 days
Inventory Charges, net (E&O and APC)	1,627	$ (15)	$ 2,288	$ 486
Adverse Purchase Commitments	(1,669)	172	(2,662)	373
Inventory Charges, Inventory Valuation, Deposit And Adverse Purchase Commitment Liability	$ (42)	$ 157	$ (374)	$ 859