Commitments and Contingencies (Details)	Mar. 31, 2021 USD ($) item $ / shares	Oct. 31, 2020 USD ($)
Commitments and Contingencies.
Deferred fee per unit \| $ / shares	$ 0.35
Deferred underwriting fee payable \| $	$ 9,660,000	$ 9,660,000
Maximum number of demands for registration of securities \| item	3

The carrying value as of balance sheet date of underwriting fees payable or deferred, classified as noncurrent.

No definition available.

Name:	pmgmu_DeferredOfferingCostsNoncurrent
Namespace Prefix:	pmgmu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant