Cash, Cash Equivalents and Available for Sale Securities (Tables)

6 Months Ended

Jun. 30, 2011

Cash, Cash Equivalents and Available for Sale Securities [Abstract]

Available-for-sale Securities [Table Text Block]

Available for sale securities, including carrying value and estimated fair values, are summarized as follows:

	As of June 30, 2011								As of December 31, 2010
	Cost		Fair Value		Carrying Value		Unrealized Gain		Cost		Fair Value		Carrying Value		Unrealized Gain
	(in thousands)
U.S. government agency notes	$	21,539	$	21,550	$	21,550	$	11	$	55,222	$	55,222	$	55,222	$	—
U.S. treasury notes	3,086		3,089		3,089		3		—		—		—		—
Corporate debt securities	63,373		63,382		63,382		9		65,055		65,058		65,058		3
Total	$	87,998	$	88,021	$	88,021	$	23	$	120,277	$	120,280	$	120,280	$	3