Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Non-cancelable operating leases expiration dates			through September 2024
Rent expense	$ 1.5	$ 1.0	$ 2.5	$ 1.9

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