Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2012

Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table presents our fair value hierarchy for our assets and liabilities measured at fair value on a recurring basis at September 30, 2012 (unaudited) (in thousands):

	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	35,309	$	—	$	—	$	35,309
Commercial paper		—		40,932		—		40,932
Short-term investments:
Commercial paper		—		36,648		—		36,648
Corporate notes and bonds		—		100,814		—		100,814
U.S. government agency securities		—		2,023		—		2,023
Total	$	35,309	$	180,417	$	—	$	215,726

Fair Value Measurements Level 3 Activity

Black-Scholes options pricing model. The inputs used in determining the fair values are discussed in detail in Note 7. Level 3 activity is as follows (in thousands):

	Level 3
Balance at June 30, 2008	$	67
Interest and other income (expense), net for change in fair value of preferred stock warrants		61
Balance at June 30, 2009		128
Interest and other income (expense), net for change in fair value of preferred stock warrants		702
Net settlement of preferred stock warrant liability		(830	)
Balance at June 30, 2010	$	—