Commitments and Contingencies - Additional Information (Details)	1 Months Ended		12 Months Ended
	Oct. 06, 2017 class	Jul. 31, 2017 class	Jan. 31, 2018 USD ($)	Jan. 31, 2017 USD ($)	Jan. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Noncancelable operating lease expiration, start year			2018
Noncancelable operating lease expiration, end year			2023
Noncancelable capital lease expiration, start year			2018
Noncancelable capital lease expiration, end year			2023
Operating leases, rent expense			$ 6,300,000	$ 5,300,000	$ 4,300,000
Number of class action lawsuits filed | class		4
Litigation reserve			0
Purchase commitment with contract manufacturer			$ 9,700,000	$ 13,500,000
California
Loss Contingencies [Line Items]
Number of class action lawsuits filed | class	3