Short-Term Investments - Schedule of Fair Values and Gross Unrealized Losses of Available-for-Sale Securities Aggregated by Investment Category (Detail) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2013	Jan. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses	$ (1)	$ (2)
Corporate notes and bonds, short-term [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value		3,570
Gross Unrealized Losses		(2)
Corporate notes and bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	3,383
Gross Unrealized Losses	$ (1)