Fair Value Measurements (Tables)

9 Months Ended

Oct. 31, 2014

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 October 31, 2014 (in thousands):

	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	43,059	$	—	$	—	$	43,059
Commercial paper		—		2,100		—		2,100
U.S. agency obligations		—		7,933		—		7,933
Short-term investments
Asset backed-securities		—		8,959		—		8,959
Corporate notes and bonds		—		50,336		—		50,336
U.S. agency obligations		—		190,225		—		190,225
U.S. treasury securities		—		11,211		—		11,211
Total	$	43,059	$	270,764	$	—	$	313,823

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