| **Employee Savings Plan (Details) (USD $)In Thousands, unless otherwise specified** | 12 Months Ended | 36 Months Ended |
|-------------------------------------------------------------------------------------|-----------------|-----------------|
||
| **Employee Savings Plan [Abstract]**                                                |            |            |   |   |
| Matching contribution (in hundredths)                                               |            |            |   | 50.00% |
| Minimum contribution as percentage of compensation (in hundredths)                  |            |            |   | 5.00% |
| Maximum contribution as percentage of compensation (in hundredths)                  |            |            |   | 8.00% |
| Contributions by employer                                                           | $ 535           | $ 597           | $ 594 |   |
| Employer discretionary contribution                                                 | $ 0             | $ 0             | $ 0 |   |

| X                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Minimum percentage of employee gross pay, by the terms of the plan, that the employer may contribute to a defined contribution plan.
+ References
No definition available.
+ Details**Name:**pgnx_DefinedContributionPlanMinimumAnnualContributionPerEmployeePercent**Namespace Prefix:**pgnx_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CompensationAndRetirementDisclosureAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of the cost recognized during the period for defined contribution plans.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 11 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.
+ Details**Name:**us-gaap_DefinedContributionPlanCostRecognized**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of discretionary contributions made by an employer to a defined contribution plan.
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent**Namespace Prefix:**us-gaap_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum percentage of employee gross pay, by the terms of the plan, that the employer may contribute to a defined contribution plan.
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedContributionPlanMaximumAnnualContributionPerEmployeePercent**Namespace Prefix:**us-gaap_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |