Supplemental Disclosure Of Cash Flows (Supplemental Disclosures Of Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Disclosure Of Cash Flows [Abstract]
Interest received	$ 425	$ 1,069	$ 381
Interest paid	77	72	680
Income taxes received	40	73
Income taxes paid	107	148	190
Acquisition of a business through contingent consideration liabilities incurred	3,705
Acquisition of a business through issuance of common stock	982
Investment in partnerships	$ 442
Self-fitting software acquired through liabilities incurred and exchange of investment in partnership		$ 3,093
Technology access liability			$ (375)