Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015	Jan. 31, 2016
Loss Contingencies [Line Items]
Net operating lease expenses	$ 2,000,000	$ 1,600,000	$ 5,600,000	$ 5,200,000
Total manufacturing purchase commitments	22,100,000		22,100,000		$ 19,700,000
Indemnification agreement [Member]
Loss Contingencies [Line Items]
Payments under indemnification obligations			0		0
Liabilities recorded under indemnification obligations	$ 0		$ 0		$ 0