Common Stock Calculation Period

No definition available.

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

- Definition

The percentage of ownership of common stock or equity participation in a related party.

+ References

No definition available.

+ Details

Name:	pgen_RelatedPartyOwnershipInterest
Namespace Prefix:	pgen_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after allowance, receivable from customers, clients, or other third-parties, and receivables classified as other due within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of cash (inflow) outflow from investing activities classified as other.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the sale and maturity (principal being due) of other investments, prepayment and call (request of early payment) of other investments not otherwise defined in the taxonomy.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Professional and contract service expense includes cost reimbursements for support services related to contracted projects, outsourced management, technical and staff support.

+ References

No definition available.

+ Details

Name:	us-gaap_ProfessionalAndContractServicesExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of sublease income excluding finance and operating lease expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980

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-Publisher FASB
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-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=pgen_FibrocellMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=pgen_ThirdSecurityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=pgen_ExecutiveChairmanformerChiefExecutiveOfficerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
	Jan. 31, 2020	Dec. 31, 2019	Nov. 30, 2015	Mar. 31, 2020	Mar. 31, 2019
Related Party Transaction [Line Items]
Common stock calculation period				30 days
Related party payables		$ 51		$ 139
Proceeds from sales of equity securities				0	$ 418
Other receivables		4,978		351
Third Security, LLC
Related Party Transaction [Line Items]
Expense for services				38	17
Sublease rental income				$ 22	22
Third Security, LLC \| Common Stock
Related Party Transaction [Line Items]
Expense for services			$ 800
Related party payables					$ 2,078
Fibrocell Science, Inc.
Related Party Transaction [Line Items]
Proceeds from sales of equity securities		1,280
Proceeds from convertible notes receivable and investment in preferred stock	$ 3,311
Other receivables		$ 3,311
Third Security, LLC \| Executive Chairman
Related Party Transaction [Line Items]
Ownership interest				100.00%