Number of options to renew under the operating leases.

No definition available.

Name:	prpo_OperatingLeaseNumberOfOptionsToRenew
Namespace Prefix:	prpo_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

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+ Details

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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

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

- Definition

Term of lessee's operating lease renewal, 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
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Name:	us-gaap_OperatingLeasePayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

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

- Definition

Amount of net investment in sales-type lease.

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

- Details

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Balance Type:
Period Type:

- Details

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- Details

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LEASES - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
LEASES - Narrative (Details) $ in Thousands	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) item	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Operating leases		$ 200	$ 200
Right-of-use assets obtained in exchange for operating lease obligations		0	0
Finance lease ROU assets		44	38
Net investment in leased assets		$ 100
Minimum
Lessee, Lease, Description [Line Items]
Facility leases \| item		1
Renewal term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal term		5 years
Net investment in leased assets				$ 100
Right of Use Asset
Lessee, Lease, Description [Line Items]
Finance lease ROU assets	$ 0		$ 0
Right of Use Asset \| Maximum
Lessee, Lease, Description [Line Items]
Finance lease ROU assets		$ 100