| Note 6 - Capital Stock, Stock Plans, Warrants, and Stock Based Compensation (Details) - Stock-based Compensation Recognized (USD $) In Thousands, unless otherwise specified | 12 Months Ended | |
|---|---|---|
| Dec. 31, 2014 | Dec. 31, 2013 | |
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Stock Options | $ 34,000us-gaap_AllocatedShareBasedCompensationExpense | $ 125,000us-gaap_AllocatedShareBasedCompensationExpense | 
| Employee Stock Option [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Stock Options | (14,000)us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_EmployeeStockOptionMember | 80,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = us-gaap_EmployeeStockOptionMember | 
| Director Stock Options [Member] | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||
| Stock Options | $ 48,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = pesi_DirectorStockOptionsMember | $ 45,000us-gaap_AllocatedShareBasedCompensationExpense / us-gaap_AwardTypeAxis = pesi_DirectorStockOptionsMember | 
| X | ||||||||||
| 
- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |