Balance Sheet Components - Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018	Jan. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 1,982		$ 1,982		$ 2,027
Less: Accumulated amortization	(1,244)		(1,244)		(979)
Intangible assets, net	738		738		1,048
Amortization of intangible assets	100	$ 200	285	$ 373
Aggregate future amortization expense
Fiscal 2020 (remaining six months)	206		206
Fiscal 2021	324		324
Fiscal 2022	123		123
Fiscal 2023	85		85
Intangible assets, net	738		738		1,048
Developed technology
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	1,246		$ 1,246		$ 1,269
Weighted-Average Remaining Useful life			15 months		15 months
Aggregate future amortization expense
Useful lives			3 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	613		$ 613		$ 632
Weighted-Average Remaining Useful life			39 months		39 months
Aggregate future amortization expense
Useful lives			5 years
Non-compete agreement
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 123		$ 123		$ 126
Weighted-Average Remaining Useful life			15 months		15 months
Aggregate future amortization expense
Useful lives			3 years