Marketable Securities (Schedule Of Unrealized Loss Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value
In Unrealized Loss Position For Less Than 12 Months	$ 21,102	$ 15,716
In Unrealized Loss Position For Greater Than 12 Months	5,263	355
Gross Unrealized Losses
In Unrealized Loss Position For Less Than 12 Months	(471)	(86)
In Unrealized Loss Position For Greater Than 12 Months	(193)	(2)
U.S. government and agency obligations
Fair Value
In Unrealized Loss Position For Less Than 12 Months	10,231	9,250
In Unrealized Loss Position For Greater Than 12 Months	4,054	0
Gross Unrealized Losses
In Unrealized Loss Position For Less Than 12 Months	(223)	(57)
In Unrealized Loss Position For Greater Than 12 Months	(157)	0
Corporate debt securities and certificates of deposit
Fair Value
In Unrealized Loss Position For Less Than 12 Months	8,665	5,188
In Unrealized Loss Position For Greater Than 12 Months	679	355
Gross Unrealized Losses
In Unrealized Loss Position For Less Than 12 Months	(197)	(18)
In Unrealized Loss Position For Greater Than 12 Months	(16)	(2)
Asset backed securities
Fair Value
In Unrealized Loss Position For Less Than 12 Months	2,206	1,278
In Unrealized Loss Position For Greater Than 12 Months	530	0
Gross Unrealized Losses
In Unrealized Loss Position For Less Than 12 Months	(51)	(11)
In Unrealized Loss Position For Greater Than 12 Months	$ (20)	$ 0