Commitments and Contingencies (Details)			1 Months Ended		3 Months Ended		9 Months Ended
	Dec. 06, 2021 USD ($)	Aug. 10, 2021 USD ($)	Feb. 29, 2020	Nov. 30, 2019 USD ($)	Jan. 31, 2022 USD ($) ft² phase	Jan. 31, 2021 USD ($)	Jan. 31, 2022 USD ($) ft² phase	Jan. 31, 2021 USD ($)	Apr. 30, 2021 USD ($)
Long-term Purchase Commitment [Line Items]
Purchase commitment, incurred cost					$ 3,800,000	$ 3,500,000	$ 10,400,000	$ 9,600,000
Lease, area under lease | ft²					283,015		283,015
Lease, total undiscounted base rent payments over term of lease					$ 103,100,000		$ 103,100,000
Lease, term of rent abatement per phase, following rent commencement date					6 months
Lease, monthly base rent					$ 500,000		500,000
Lessee, tenant improvement allowance					$ 44,200,000		$ 44,200,000
Lease, term					126 months		126 months
Lease, period after date phase one delivered					9 months		9 months
Lease, number of phases | phase					2		2
Operating lease, liability					$ 26,500,000		$ 26,500,000
Operating lease, right-of-use assets					26,500,000		26,500,000
Blattman et al. v. Siebel et al. | Pending Litigation
Long-term Purchase Commitment [Line Items]
Recommended amount to be awarded from other party		$ 9,700,000
Requested by plaintiff, amount to be awarded from other party		$ 8,300,000
Blattman et al. v. Siebel et al. | Settled Litigation
Long-term Purchase Commitment [Line Items]
Amount awarded from other party	$ 9,400,000
Blattman et al. v. Siebel et al. | Settled Litigation | Other Income (Expense)
Long-term Purchase Commitment [Line Items]
Amount awarded from other party					9,400,000		9,400,000
Landlord | Letter of Credit | Line of Credit
Long-term Purchase Commitment [Line Items]
Letter of credit outstanding					12,600,000		12,600,000
Maximum
Long-term Purchase Commitment [Line Items]
Lease, monthly base rent					1,000,000		1,000,000
C3.ai DTI Grants Program
Long-term Purchase Commitment [Line Items]
Grants, payment period			5 years
Grants, potential remaining contributions					$ 34,500,000		$ 34,500,000		$ 43,100,000
Web-Hosting Services, November 2019-November 2022
Long-term Purchase Commitment [Line Items]
Purchase commitment				$ 30,000,000
Purchase commitment, term				3 years
Web-Hosting Services, November 2020
Long-term Purchase Commitment [Line Items]
Purchase commitment				$ 10,000,000
Web-Hosting Services, November 2021
Long-term Purchase Commitment [Line Items]
Purchase commitment				10,000,000
Web-Hosting Services, November 2022
Long-term Purchase Commitment [Line Items]
Purchase commitment				$ 10,000,000