Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Deferred tax assets:
Federal and state credits	$ 19,426	$ 18,176
Expenses not currently deductible	575	1,213
Stock-based compensation	3,202	2,899
Foreign deferred	122	229
Gross deferred tax assets	23,325	22,517
Valuation allowance	(12,526)	(18,538)
Total deferred tax assets	10,799	3,979
Deferred tax liabilities
Property and equipment	(1,505)	(1,655)
Net deferred tax assets	$ 9,294	$ 2,324