Leases - Schedule of Cumulative Effect of Changes to Condensed Consolidated Balance Sheet for Adoption of Topic 842 (Detail) - USD ($) $ in Thousands	Apr. 30, 2019	Feb. 01, 2019	Jan. 31, 2019
Leases Disclosure [Line Items]
Operating lease right-of-use assets	$ 7,911		$ 0
Prepaid expenses and other current assets	5,025		6,206
Accrued and other current liabilities	22,523		24,700
Operating lease liabilities, current	2,390		0
Operating lease liabilities, non-current	$ 5,635		$ 0
Leases (Topic 842) [Member]
Leases Disclosure [Line Items]
Operating lease right-of-use assets		$ 8,581
Prepaid expenses and other current assets		6,032
Accrued and other current liabilities		24,421
Operating lease liabilities, current		2,534
Operating lease liabilities, non-current		6,152
Leases (Topic 842) [Member] | Restatement Adjustment [Member]
Leases Disclosure [Line Items]
Operating lease right-of-use assets		8,581
Prepaid expenses and other current assets		(174)
Accrued and other current liabilities		(279)
Operating lease liabilities, current		2,534
Operating lease liabilities, non-current		$ 6,152