Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Fair Value Measurements [Abstract]

Assets and liabilities measured at fair value on a recurring basis

	June 30, 2012
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents:
Money market funds	$	7,442	$	—	$	—	$	7,442
Corporate debt		—		750		—		750
Total cash equivalents		7,442		750		—		8,192
Short-term investments:
Municipal securities		—		355		—		355
Corporate commercial paper		—		2,299		—		2,299
Foreign government bonds		—		501		—		501
Corporate debt		—		6,247		—		6,247
Total short-term investments		—		9,402	$	—		9,402
Restricted cash—money market fund		875		—		—		875
Total assets	$	8,317	$	10,152	$	—	$	18,469
MPC earn-out liability	$	—	$	—	$	696	$	696

	December 31, 2011
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents:
Money market funds	$	6,576	$	—	$	—	$	6,576
Corporate debt		—		501		—		501
Total cash equivalents		6,576		501		—		7,077
Short-term investments:
U.S. agency securities		—		1,751		—		1,751
Municipal securities		—		355		—		355
Corporate commercial paper		—		1,250		—		1,250
Foreign government bonds		—		500		—		500
Corporate debt		—		5,763		—		5,763
Total short-term investments		—		9,619	$	—		9,619
Restricted cash—money market fund		875		—		—		875
Total assets	$	7,451	$	10,120	$	—	$	17,571
MPC earn-out liability	$	—	$	—	$	766	$	766