Income Taxes - Summary of Significant Components of Company's Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 49,100	$ 38,049
Accruals and reserves	1,164	2,196
Stock-based compensation	3,388	1,256
Tax credits	2,233	1,074
Gross deferred tax assets	55,885	42,575
Valuation allowance	(54,615)	(41,484)
Total deferred tax assets, net of valuation allowance	1,270	1,091
Deferred tax liabilities:
Fixed assets and intangibles assets	(1,072)	(1,104)
Gross deferred tax liabilities	(1,072)	(1,104)
Net deferred tax liabilities		$ (13)
Net deferred tax assets	$ 198