Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Equipment, leaseholds and intangible amortization, net	$ 202	$ 217
Inventory allowances	573	563
Accrued expenses	250	139
Warranty accrual	170	165
Deferred revenue	267	155
Accounts receivable allowance	68	102
Federal and state tax credits	4,021	3,818
Federal and state net operating loss carry forwards	1,508	2,237
Share-based compensation	314	289
Other, net	54	50
Subtotal	7,427	7,735
Valuation allowance	(1,557)	(1,606)
Total deferred tax assets	5,870	6,129
Liabilities
Equipment, leaseholds and intangible amortization, net	448	387
Inventory allowances	0	0
Subtotal	448	387
Total deferred tax liabilities	$ 448	$ 387