Fair Value Measurements (Tables)

12 Months Ended

Jan. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Hierarchy for Financial Assets Measured at Fair Value on Recurring Basis

The following table presents the fair value hierarchy for financial assets measured at fair value on a recurring basis as of January 31, 2015 (in thousands):

	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	41,861	$	—	$	—	$	41,861
U.S. agency obligations		—		3,595		—		3,595
Short-term investments
Asset backed-securities		—		9,319		—		9,319
Commercial paper		—		3,394		—		3,394
Corporate notes and bonds		—		45,989		—		45,989
U.S. agency obligations		—		199,911		—		199,911
U.S. treasury securities		—		10,007		—		10,007
Total	$	41,861	$	272,215	$	—	$	314,076

The following table presents the fair value hierarchy for financial assets measured at fair value on a recurring basis as of January 31, 2014 (in thousands):

	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	170,235	$	—	$	—	$	170,235
Commercial paper		—		9,999		—		9,999
U.S. treasury securities		—		33,153		—		33,153
Short-term investments:
Corporate notes and bonds		—		10,507		—		10,507
U.S. agency obligations		—		15,118		—		15,118
Total	$	170,235	$	68,777	$	—	$	239,012