Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Concentration Risk [Line Items]
Net foreign currency transaction gains (losses)	$ 6,000,000	$ (2,600,000)	$ (2,300,000)
Restricted cash	14,763,000	12,734,000
Acquisition of intangible assets	0	1,000,000	0
Impairment charges	0	0	0
Deferred commissions, current	22,437,000	15,787,000
Deferred income taxes, non-current	20,300,000	14,900,000
Sales commission expenses	$ 119,800,000	84,800,000	47,200,000
Period required with included controller refresh to have additional maintenance and support renewal	3 years
Additional maintenance and support period	3 years
Warranty reserve	$ 0
Capitalization of software development cost	0	0	0
Advertising expenses	$ 10,300,000	$ 10,700,000	$ 6,200,000
Hardware
Concentration Risk [Line Items]
Standard product warranty period	3 years
Embedded Software
Concentration Risk [Line Items]
Standard product warranty period	90 days
Technology patents
Concentration Risk [Line Items]
Acquisition of intangible assets	$ 1,000,000
Minimum
Concentration Risk [Line Items]
Contractual term	1 year
Minimum | Technology patents
Concentration Risk [Line Items]
Estimated useful life of intangible assets	5 years
Maximum
Concentration Risk [Line Items]
Contractual term	5 years
Maximum | Technology patents
Concentration Risk [Line Items]
Estimated useful life of intangible assets			7 years
Test equipment
Concentration Risk [Line Items]
Property and equipment, useful life	2 years
Computer equipment and software | Minimum
Concentration Risk [Line Items]
Property and equipment, useful life	2 years
Computer equipment and software | Maximum
Concentration Risk [Line Items]
Property and equipment, useful life	3 years
Furniture and fixtures
Concentration Risk [Line Items]
Property and equipment, useful life	7 years
Customer concentration risk | Sales revenue net
Concentration Risk [Line Items]
Concentration risk percentage		11.00%