Revenue Recognition - (Summary of the amounts reclassified from beginning contract liabilities to revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
REVENUE RECOGNITION - TOPIC 606
Amounts reclassified from beginning contract liabilities to revenue	$ 334	$ 354
Amounts reclassified from deferred warranty revenue	213	225
Total	$ 547	$ 579

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

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