Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Loss Contingencies [Line Items]
Net operating lease expenses	$ 4,600,000	$ 5,300,000	$ 7,600,000
Amortization of intangible assets	4,650,000	2,981,000	$ 50,000
Total manufacturing purchase commitments	28,200,000	24,300,000
Indemnification agreement [Member]
Loss Contingencies [Line Items]
Payments under indemnification obligations	0	0
Liabilities recorded under indemnification obligations	0	0
Internal-use software license [Member]
Loss Contingencies [Line Items]
Amortization of intangible assets	$ 4,700,000	$ 3,000,000