Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2012

Summary of Significant Accounting Policies [Abstract]

Fair Value Measurements

	June 30, 2012						December 31, 2011
	Level 1		Level 2		Total		Level 1		Level 2		Total
Assets:
Cash and cash equivalents:
Money market funds	$	80,781	$	—	$	80,781	$	77,174	$	—	$	77,174
Commercial paper		—		7,999		7,999		—		4,798		4,798
Short-term investments:
Commercial paper		—		15,744		15,744		—		12,097		12,097
U.S. government agency bonds		—		4,355		4,355		—		—		—
Total	$	80,781	$	28,098	$	108,879	$	77,174	$	16,895	$	94,069
Liabilities:
Interest rate swap contracts (1)	$	—	$	1,164	$	1,164	$	—	$	1,005	$	1,005
Total	$	—	$	1,164	$	1,164	$	—	$	1,005	$	1,005

(1) As of June 30, 2012 and December 31, 2011, the fair value of the interest rate swap contracts were classified on our Balance Sheet in “Other non-current liabilities”.