Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Fair Value Measurements [Abstract]

Schedule of assets and liabilities measured at fair value on recurring basis

June 30, 2012	Total		Level 1		Level 2		Level 3		Valuation Technique
Assets
Money market mutual funds	$	10,158	$	10,158	$	—	$	—		(a	)
Government agency bonds		4,008		4,008		—		—		(a	)
Corporate notes		3,686		3,686		—		—		(a	)
United States treasuries		3,005		3,005		—		—		(a	)
Certificates of deposit		1,925		1,925		—		—		(a	)
Liabilities
Interest rate swaps	$	553	$	—	$	553	$	—		(d	)

December 31, 2011	Total		Level 1		Level 2		Level 3		Valuation Technique
Assets
Government agency bonds	$	9,015	$	9,015	$	—	$	—		(a	)
Money market mutual funds		8,818		8,818		—		—		(a	)
Corporate notes		3,019		3,019		—		—		(a	)
Certificates of deposit		2,701		2,701		—		—		(a	)
Liabilities
Interest rate swaps	$	510	$	—	$	510	$	—		(d	)