Revenue Information - Revenue into Primary Product Groups and Major Regions (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue [Line Items]
Revenue	$ 6,357	$ 6,420	$ 12,091	$ 12,725
North and South America [Member]
Revenue [Line Items]
Revenue	4,003	3,493	7,355	7,253
Asia (including Middle East) and Australia [Member]
Revenue [Line Items]
Revenue	1,580	1,969	2,996	3,833
Europe and Africa [Member]
Revenue [Line Items]
Revenue	774	958	1,740	1,639
Audio conferencing [Member]
Revenue [Line Items]
Revenue	2,648	2,889	5,435	5,600
Microphones [Member]
Revenue [Line Items]
Revenue	1,891	2,230	4,034	4,336
Video products [Member]
Revenue [Line Items]
Revenue	$ 1,818	$ 1,301	$ 2,622	$ 2,789

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Name:	us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration