Goodwill and Intangible Assets, net - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Apr. 30, 2017	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Goodwill [Line Items]
Goodwill recorded in connection with Stormpath acquisition		$ 3,652,000
Goodwill impairments		0	$ 0	$ 0
Amortization expense		2,900,000	1,800,000	900,000
Reversal of previously capitalized costs		1,114,000	0	0
Stormpath Inc.
Goodwill [Line Items]
Goodwill recorded in connection with Stormpath acquisition	$ 3,652,000
Capitalized internal-use software costs
Goodwill [Line Items]
Acquired intangibles		6,700,000	6,100,000
Stock-based compensation included in capitalized software costs		1,200,000	600,000
Amortization expense		2,700,000	1,600,000	$ 700,000
Reversal of previously capitalized costs		1,077,000	0
Software licenses
Goodwill [Line Items]
Acquired intangibles		0	400,000
Reversal of previously capitalized costs		$ 37,000	$ 0