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

9 Months Ended

Sep. 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 September 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	$	14,917	$	14,919	$	14,919	$	2		$	55,222	$	55,222	$	55,222	$	—
U.S. treasury notes	3,054		3,056		3,056		2			—		—		—		—
Corporate debt securities	31,765		31,764		31,764		(1		)	65,055		65,058		65,058		3
Total	$	49,736	$	49,739	$	49,739	$	3		$	120,277	$	120,280	$	120,280	$	3