Investments (Tables)

6 Months Ended

Jun. 30, 2012

Available-For-Sale Investments

The amortized cost and fair market values of available-for-sale investments are as follows at June 30, 2012 and December 31, 2011 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Market Value
June 30, 2012
Money market investments	$	1,094	$	—	$	—	$	1,094
Mortgage-backed securities		2,833		89		1		2,921
Corporate bonds and direct obligations of government agencies		73,427		1,070		32		74,465
U.S. Treasury obligations		12,999		47		2		13,044
Total	$	90,353	$	1,206	$	35	$	91,524
December 31, 2011
Money market investments	$	1,989	$	—	$	—	$	1,989
Mortgage-backed securities		3,017		61		18		3,060
Corporate bonds and direct obligations of government agencies		51,014		819		126		51,707
U.S. Treasury obligations		11,682		51		1		11,732
Total	$	67,702	$	931	$	145	$	68,488

Schedule of Unrealized Loss on Investments

For those available-for-sale investments with unrealized losses at June 30, 2012 and December 31, 2011, the following table summarizes the duration of the unrealized loss (in thousands):

	Less than 12 months				12 months or longer				Total
	Fair Market Value		Unrealized Loss		Fair Market Value		Unrealized Loss		Fair Market Value		Unrealized Loss
June 30, 2012
Mortgage-backed securities	$	546	$	1	$	—	$	—	$	546	$	1
Corporate bonds and direct obligations of government agencies		5,911		11		478		21		6,389		32
U.S. Treasury obligations		11,291		2		—		—		11,291		2
Total	$	17,748	$	14	$	478	$	21	$	18,226	$	35
December 31, 2011
Mortgage-backed securities	$	468	$	18	$	—	$	—	$	468	$	18
Corporate bonds and direct obligations of government agencies		6,067		126		—		—		6,067		126
U.S. Treasury obligations		591		1		—		—		591		1
Total	$	7,126	$	145	$	—	$	—	$	7,126	$	145