Summary of Significant Accounting Policies - Cash and Cash Equivalents - Additional Information (Details)	6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
Highly liquid investment maximum maturity period	3 months

Original maturity period for highly liquid investments to be considered cash equivalent, maximum

No definition available.

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Namespace Prefix:	pgen_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration