Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value of Financial Assets and Liabilities Measured on Recurring Basis

The following table sets forth the fair value of our financial assets and liabilities, allocated into Level 1, Level 2 and Level 3, that were measured on a recurring basis (in thousands):

	June 30, 2015
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	20,483	$	—	$	—	$	20,483
Corporate notes and commercial paper	—			214,566		—		214,566
U.S. government agency securities		—		155,805		—		155,805
Total financial assets	$	20,483	$	370,371	$	—	$	390,854

	December 31, 2014
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	24,915	$	—	$	—	$	24,915
Corporate notes and commercial paper		—		226,047		—		226,047
U.S. government agency securities		—		120,169		—		120,169
Total financial assets	$	24,915	$	346,216	$	—	$	371,131