Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | segment	2
Revenue recognized after shipment because the customer has the right to return the product during this trial period phase, in days	60 days
Number of days for notification of product defect	30 days
Warranty term	1 year
Allowance for doubtful accounts	$ 170	$ 135
Depreciation expense	1,870	1,524	$ 1,955
Impairment of long-lived assets from continuing operations	0
Impairment of goodwill or intangible assets	0
Amortization expense	$ 159	$ 231	$ 227
Maximum term	6 years	6 years	6 years
Research and development	$ 4,688	$ 4,279	$ 4,291
Minimum [Member]
Significant Accounting Policies [Line Items]
Acquired finite-lived intangible assets amortization period	18 years
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]
Acquired finite-lived intangible assets amortization period	20 years
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%
Hearing Help Express (HHE) [Member]
Significant Accounting Policies [Line Items]
Ownership percentage	20.00%
Customer Funded Tooling [Member]
Significant Accounting Policies [Line Items]
Research and development	$ 102	$ 121	$ 140