Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	$ 135	$ 120
Number of days for notification of product defect	30 days
Warranty term	1 year
Depreciation expense	$ 1,524	1,955	$ 2,214
Impairment of long-lived assets from continuing operations	0
Impairment of goodwill or intangible assets	0
Interest expense	72	56	35
Amortization expense	231	227	$ 204
Deferred tax asset valuation allowance	$ 9,810	$ 10,105
Maximum term	6 years	6 years	6 years
Research and development	$ 5,214	$ 4,832	$ 4,181
Accrued research and development tax credit grant refunds			567
Minimum [Member] | Building and Improvements [Member]
Significant Accounting Policies [Line Items]
Estimated useful life	5 years
Minimum [Member] | Machinery and Equipment [Member]
Significant Accounting Policies [Line Items]
Estimated useful life	3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Vesting period of options under equity incentive plan	3 years
Maximum term	10 years
Maximum [Member] | Building and Improvements [Member]
Significant Accounting Policies [Line Items]
Estimated useful life	40 years
Maximum [Member] | Machinery and Equipment [Member]
Significant Accounting Policies [Line Items]
Estimated useful life	12 years
earVenture [Member]
Significant Accounting Policies [Line Items]
Ownership percentage	50.00%
Customer Funded Tooling [Member]
Significant Accounting Policies [Line Items]
Research and development	$ 121	$ 140	$ 352