NET SALES SERVICE REVENUE AND ACCOUNTS RECEIVABLE (Schedule of Allowance for Doubtful Accounts) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Allowance for doubtful accounts, Beginning balance	$ (1,127)
Allowances for dubtful accounts	(84)	$ (55)
Bad debt expense	3
Total charges	(81)
Allowance for doubtful accounts, Ending balance	(1,208)
Medicaid [Member]
Allowances for dubtful accounts	(11)	(2)
Medicare [Member]
Allowances for dubtful accounts	(20)	(30)
Self-Pay [Member]
Allowances for dubtful accounts		(4)
Third-Party Payor [Member]
Allowances for dubtful accounts	$ (53)	$ (19)

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of increase (decrease) in the allowance for doubtful accounts.

+ References

No definition available.

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of recoveries of receivables doubtful of collection that were previously charged off.

+ References

No definition available.

+ Details

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

- Definition

The aggregate selling price reductions recognized during an accounting period due to the rendering of deficient or nonconforming services. Allowances are a deduction from gross revenue in arriving at net revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Details

Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=prpo_MedicaidMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=prpo_MedicareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=us-gaap_SelfPayMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=us-gaap_ThirdPartyPayorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: