INCOME TAXES - Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 15,618	$ 7,727
Stock-based compensation expense	908	577
Tax credit carryforwards	576	311
Other	194	216
Total deferred tax assets	17,296	8,831
Less: Valuation allowance	$ (17,296)	$ (8,831)