Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Income Tax Contingency [Line Items]
Federal statutory income tax rate		33.80%	33.80%	33.80%
Net operating loss carryforwards for federal		$ 0
Net operating loss carryforwards for state		$ 4,100,000
Federal net operating loss expire year		2033
State net operating loss expire year		2033
Percentage of likely of being realized upon the effective settlement		50.00%
Gross unrecognized tax benefits		$ 11,398,000	$ 7,868,000	$ 5,248,000	$ 3,247,000
Unrecognized tax benefits, that would impact tax rate if recognized		$ 5,900,000
California [Member]
Income Tax Contingency [Line Items]
Open tax years		2014
Federal [Member]
Income Tax Contingency [Line Items]
Open tax years		2015
Other states [Member]
Income Tax Contingency [Line Items]
Open tax years		2014
Foreign Jurisdictions [Member]
Income Tax Contingency [Line Items]
Open tax years		2013
Maximum [Member]
Income Tax Contingency [Line Items]
Federal statutory income tax rate		35.00%
Scenario Plan [Member]
Income Tax Contingency [Line Items]
Federal statutory income tax rate	21.00%
California research and development [Member]
Income Tax Contingency [Line Items]
Research and development tax credits		$ 15,900,000