Financial Instruments and Fair Value - Schedule of Cash Equivalents and Marketable Securities (Detail) - USD ($) $ in Thousands	Oct. 31, 2015	Jan. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Total cash equivalents and marketable securities	$ 40,296	$ 40,130
Included in cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Total cash equivalents and marketable securities	41	2,427
Included in marketable securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total cash equivalents and marketable securities	$ 40,255	$ 37,703