Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

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):

	September 30, 2015
	Level 1		Level 2		Level 3		Total
Financial Assets:
Money market funds	$	21,351	$	—	$	—	$	21,351
Corporate notes and commercial paper	—			181,962		—		181,962
U.S. government agency securities		—		140,056		—		140,056
Total financial assets	$	21,351	$	322,018	$	—	$	343,369
	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