Goodwill and Intangible Assets, net - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
	Oct. 31, 2017	Apr. 30, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016	Jan. 31, 2017
Goodwill [Line Items]
Goodwill	$ 6,282,000			$ 6,282,000		$ 2,630,000
Goodwill impairments	0		$ 0	0	$ 0
Capitalized internal-use software	1,700,000		1,900,000	5,000,000	4,400,000
Amortization expense	800,000		500,000	2,100,000	1,300,000
Stormpath Inc.
Goodwill [Line Items]
Goodwill, acquired during period		$ 3,700,000
Capitalized internal-use software costs
Goodwill [Line Items]
Stock-based compensation included in capitalized software costs	300,000		$ 200,000	$ 900,000	$ 400,000
Research and development expense
Goodwill [Line Items]
Reversal of previously capitalized costs	$ 500,000