Subsequent events - Narrative (Details) - Subsequent Event $ in Millions	Aug. 25, 2021 USD ($) ft²
Subsequent Event [Line Items]
Lease not yet commenced, area under lease \| ft²	283,015
Lease not yet commenced, total undiscounted base rent payments over term of lease	$ 103.1
Lease not yet commenced, term of rent abatement per phase, following rent commencement date	6 months
Lease not yet commenced, monthly base rent	$ 0.5
Lease not yet commenced, tenant improvement allowance	$ 44.2
Lease not yet commenced, term	126 months
Lease not yet commenced, period after date phase one delivered	9 months
Letter of Credit \| Line of Credit \| Landlord
Subsequent Event [Line Items]
Letter of credit outstanding	$ 12.6
Maximum
Subsequent Event [Line Items]
Lease not yet commenced, monthly base rent	$ 1.0

Lessee, Operating Lease, Lease Not Yet Commenced, Amount

No definition available.

Name:	ai_LesseeOperatingLeaseLeaseNotYetCommencedAmount
Namespace Prefix:	ai_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessee, Operating Lease, Lease Not Yet Commenced, Area Under Lease

+ References

No definition available.

+ Details

Name:	ai_LesseeOperatingLeaseLeaseNotYetCommencedAreaUnderLease
Namespace Prefix:	ai_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Lessee, Operating Lease, Lease Not Yet Commenced, Tenant Improvement Allowance

+ References

No definition available.

+ Details

Name:	ai_LesseeOperatingLeaseLeaseNotYetCommencedTenantImprovementAllowance
Namespace Prefix:	ai_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lessee, Operating Lease, Lease Not Yet Commenced, Term Of Contract, Period After Date Phase One Delivered

+ References

No definition available.

+ Details

Name:	ai_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContractPeriodAfterDatePhaseOneDelivered
Namespace Prefix:	ai_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Lessee, Operating Lease, Lease Not Yet Commenced, Term Of Rent Abatement Per Phase, Following Rent Commencement Date

+ References

No definition available.

+ Details

Name:	ai_LesseeOperatingLeaseLeaseNotYetCommencedTermOfRentAbatementPerPhaseFollowingRentCommencementDate
Namespace Prefix:	ai_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Lessee, Operating Lease, Lease Not Yet Commenced, Undiscounted Amount

+ References

No definition available.

+ Details

Name:	ai_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount
Namespace Prefix:	ai_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Term of lessee's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=ai_LandlordMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: