Commitments and Contingencies - Additional Information (Details)	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2017 class	Jul. 31, 2017 class	Oct. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Oct. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Jan. 31, 2017 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			$ 1,600,000	$ 1,500,000	$ 4,700,000	$ 3,800,000
Number of class action lawsuits filed | class		4
Litigation reserve			0		0
Purchase commitment with contract manufacturer			$ 18,700,000		$ 18,700,000		$ 13,500,000
California
Loss Contingencies [Line Items]
Number of class action lawsuits filed | class	3