Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2012

Marketable Securities [Abstract]

Schedule of Marketable Securities

marketable securities were classified as held-to-maturity for the dates presented and the carrying amounts of held-to-maturity securities were as follows (in thousands):

December 31,	2012		2011
U.S. Government and agency obligations	$	7,375	$	40,240
Commercial paper	34,966		24,980
Municipal bonds	8,738		2,057
Corporate bonds	5,009		3,131
Total short-term marketable securities	56,088		70,408
U.S. Government and agency obligations	55,342		65,109
Municipal bonds	—		8,909
Corporate bonds	—		5,232
Total long-term marketable securities	55,342		79,250
Total marketable securities	$	111,430	$	149,658

Held-to-maturity Securities

Scheduled maturities of held-to-maturity investments were as follows (in thousands):

December 31, 2012
Due within one year	$	56,088
Due in one to five years	55,342
Total	$	111,430