Investments (Tables)

12 Months Ended

Dec. 31, 2011

Investments [Abstract]

Available-For-Sale Investments

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Market Value
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
December 25, 2010
Money market investments	$	535	$	—	$	—	$	535
Mortgage-backed securities		3,458		64		8		3,514
Corporate bonds and direct obligations of government agencies		60,330		872		151		61,051
U.S. Treasury obligations		12,584		6		23		12,567
Total	$	76,907	$	942	$	182	$	77,667

Schedule Of Unrealized Loss On Investments

	Less than 12 months				12 months or longer				Total
	Fair Market Value		Unrealized Loss		Fair Market Value		Unrealized Loss		Fair Market Value		Unrealized Loss
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
December 25, 2010
Mortgage-backed securities	$	225	$	8	$	—	$	—	$	225	$	8
Corporate bonds and direct obligations of government agencies		11,615		151		—		—		11,615		151
U.S. Treasury obligations		774		23		—		—		774		23
Total	$	12,614	$	182	$	—	$	—	$	12,614	$	182