Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019
Deferred tax assets:
Federal and state credits	$ 21,275	$ 19,426
Expenses not currently deductible	593	575
Operating lease liabilities	2,023	0
Stock-based compensation	3,203	3,202
Foreign deferred	132	122
Gross deferred tax assets	27,226	23,325
Valuation allowance	(14,670)	(12,526)
Total deferred tax assets	12,556	10,799
Deferred tax liabilities
Property and equipment	(1,469)	(1,505)
Operating lease assets	(1,974)	0
Net deferred tax assets	$ 9,113	$ 9,294