Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015
Deferred tax assets:
Federal and state credits	$ 11,852	$ 6,465
Expenses not currently deductible	2,331	1,590
Stock-based compensation	2,503	2,044
Gross deferred tax assets	16,686	10,099
Valuation allowance	(12,072)	(3,996)
Total deferred tax assets	4,614	6,103
Deferred tax liabilities
Property and equipment	(1,378)	(199)
Foreign deferred	(33)	(70)
Net deferred tax assets	$ 3,203	$ 5,834