Income Taxes - Summary of Tax Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 12,072
Balance at End of Period	15,061	$ 12,072
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	12,072	3,996	$ 2,302
Additional Charged to Expenses	2,989	8,076	1,694
Additions Charged to Other Account	0	0	0
Deductions Charged to Expenses or Other Accounts	0	0	0
Balance at End of Period	$ 15,061	$ 12,072	$ 3,996