Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Loss Contingencies [Line Items]
Net operating lease expenses	$ 7,600,000	$ 6,800,000	$ 5,800,000
Total manufacturing purchase commitments	23,900,000	19,700,000
Indemnification agreement [Member]
Loss Contingencies [Line Items]
Payments under indemnification obligations	0	0
Liabilities recorded under indemnification obligations	$ 0	$ 0