Summary of Significant Accounting Policies (Details 3) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Total cost	$ 11,556	$ 24,346
Accumulated depreciation and amortization	(10,741)	(17,236)
Property and equipment, net	815	7,110
Machinery, equipment and tooling [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost	6,105	17,769
Leasehold improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost	4,624	4,624
Information systems [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost	819	991
Furniture and fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost	8	699
Construction in progress [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost		$ 263