Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Non-cancelable operating leases expiration dates	through September 2020
Rent expense	$ 3.8	$ 2.4	$ 1.4

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

No definition available.

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration