Goodwill and Acquired Intangible Assets, Net - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jan. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 21,055	$ 4,455
Accumulated Amortization	(5,161)	(2,828)
Net Book Value	15,894	1,627	[1]
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	7,400	4,300
Accumulated Amortization	(4,358)	(2,723)
Net Book Value	3,042	1,577
Domain name
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	155	155
Accumulated Amortization	(128)	(105)
Net Book Value	27	$ 50
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	13,500
Accumulated Amortization	(675)
Net Book Value	$ 12,825

[1] See Note 2 for a summary of adjustments.