Inventories (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Inventory, Net [Abstract]
Raw materials	$ 10,235		$ 10,235		$ 9,219
Work-in-process	122		122		1,195
Finished goods	7,512		7,512		10,762
Inventory, Gross	17,869		17,869		21,176
Less: inventory valuation allowance	(3,054)		(3,054)		(2,701)
Inventories, net	14,815		14,815		18,475
Other Inventory, Materials, Supplies and Merchandise under Consignment, Gross	4,800		4,800		$ 2,600
Inventory Charges, Inventory Valuation, Deposit And Adverse Purchase Commitment Liability	312	$ 182	272	$ 1,344
Adverse Purchase Commitments	$ 431	$ 281	$ 1,007	$ 154