Employee Benefits (Details) - USD ($)	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021
Employee Benefits
Defined contribution plan, employer matching contribution amount	$ 156,000	$ 40,000

Defined contribution plan, employer matching contribution amount.

No definition available.

Name:	rain_DefinedContributionPlanEmployerMatchingContributionAmount
Namespace Prefix:	rain_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration