Summary of Significant Accounting Policies (Rollforward Analysis of the Allowance Against Accounts Receivable Balance) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Abstract]
Balance at beginning of year	$ (2,535)	$ (7,033)	$ (5,211)
Bad debt recovery (charge)	341	77	(452)
Reclassification of leasehold costs related to signing bonus		4,197
Reclassification of Sojitz acquisition			(694)
Adjustment associated with settlement of customs audit	623
Foreign currency gain	63	224	(676)
Balance at end of period	$ (1,508)	$ (2,535)	$ (7,033)