Balance Sheet Components - Schedule of Amortization Expense For Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Total amortization of acquired intangible assets	$ 10,068	$ 2,956	$ 2,027
Cost of revenue | License - self-managed
Finite-Lived Intangible Assets [Line Items]
Total amortization of acquired intangible assets	948	387	387
Cost of revenue | Subscription - self-managed and SaaS
Finite-Lived Intangible Assets [Line Items]
Total amortization of acquired intangible assets	5,820	2,421	1,521
Sales and marketing
Finite-Lived Intangible Assets [Line Items]
Total amortization of acquired intangible assets	$ 3,300	$ 148	$ 119