Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Total cost	$ 10,886	$ 11,556
Accumulated depreciation and amortization	(10,474)	(10,741)
Property and equipment, net	412	815
Machinery, equipment and tooling [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost	5,435	6,105
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	819
Furniture and fixtures [Member]
Summary Of Significant Accounting Policies [Line Items]
Total cost	$ 8	$ 8