Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2011

Marketable Securities [Abstract]

Schedule Of Marketable Securities

(in thousands)	December 31, 2011
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Marketable securities:
Municipal bonds	$	27,968		74		(2	)	$	28,040
Corporate bonds		15,058		16		(34	)		15,040
Government sponsored enterprise bonds		8,001		2		(4	)		7,999
Marketable securities	$	51,027		92		(40	)	$	51,079
(in thousands)	December 31, 2010
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Marketable securities:
Government sponsored enterprise bonds	$	5,601		1		(9	)	$	5,593
Corporate bonds		5,468		—		(49	)		5,419
Commercial paper		2,999		—		(1	)		2,998
Municipal bonds		2,114		—		—			2,114
Marketable securities	$	16,182		1		(59	)	$	16,124