Marketable Securities (Schedule Of Marketable Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Gain (Loss) on Investments [Line Items]
Unrealized Gains	$ 57
Unrealized Losses		$ (11)
Marketable securities - Short-Term
Gain (Loss) on Investments [Line Items]
Cost	5,184	5,252
Unrealized Gains	6	0
Unrealized Losses	0	(3)
Fair Value	5,190	5,249
Marketable securities - Short-Term | U.S. government and agency obligations
Gain (Loss) on Investments [Line Items]
Cost	3,744	3,806
Unrealized Gains	5	0
Unrealized Losses	0	(2)
Fair Value	3,749	3,804
Marketable securities - Short-Term | Corporate debt securities and certificates of deposit
Gain (Loss) on Investments [Line Items]
Cost	1,440	1,440
Unrealized Gains	1	0
Unrealized Losses	0	(1)
Fair Value	1,441	1,439
Marketable securities - Short-Term | Asset backed securities
Gain (Loss) on Investments [Line Items]
Cost		6
Unrealized Gains		0
Unrealized Losses		0
Fair Value		6
Marketable securities - Long-Term
Gain (Loss) on Investments [Line Items]
Cost	7,176	8,092
Unrealized Gains	51	12
Unrealized Losses	0	(20)
Fair Value	7,227	8,084
Marketable securities - Long-Term | U.S. government and agency obligations
Gain (Loss) on Investments [Line Items]
Cost	6,432	6,681
Unrealized Gains	40	1
Unrealized Losses	0	(18)
Fair Value	6,472	6,664
Marketable securities - Long-Term | Corporate debt securities and certificates of deposit
Gain (Loss) on Investments [Line Items]
Cost	250	675
Unrealized Gains	1	0
Unrealized Losses	0	(1)
Fair Value	251	674
Marketable securities - Long-Term | Asset backed securities
Gain (Loss) on Investments [Line Items]
Cost	452	694
Unrealized Gains	0	0
Unrealized Losses	0	(1)
Fair Value	452	693
Marketable securities - Long-Term | Equity security
Gain (Loss) on Investments [Line Items]
Cost	42	42
Unrealized Gains	10	11
Unrealized Losses	0	0
Fair Value	$ 52	$ 53