Property and Equipment, Net (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Machinery and equipment	$ 33,109	$ 33,163
Leasehold improvements	72,961	73,363
Furniture, fixtures, and other	19,776	19,358
Construction-in-progress	992	6,809
Property and equipment	126,838	132,693
Less: Accumulated depreciation and amortization	(91,806)	(88,603)
Property and equipment, net	$ 35,032	$ 44,090