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           Commitments and Contingencies (Detail Textuals) (USD $) 
        In Millions, unless otherwise specified  | 
        0 Months Ended | 
|---|---|
| 
           Dec. 10, 2013 
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| Commitment And Contingencies [Line Items] | |
| HVAC improvement allowance | $ 0.35opxs_LeaseImprovementAllowance | 
| From 1/1/14 -3/31/14 | |
| Commitment And Contingencies [Line Items] | |
| Annual base rent rate per square foot | 
0.00opxs_AnnualBaseRentRatePerSquareFoot / opxs_LeasePeriodAxis = opxs_FromJanuary1St2014ToMarch31St2014Member  | 
      
| From 4/1/2014 - 3/31/2018 | |
| Commitment And Contingencies [Line Items] | |
| Annual base rent rate per square foot | 
5.45opxs_AnnualBaseRentRatePerSquareFoot / opxs_LeasePeriodAxis = opxs_FromApril1St2014ToMarch31St2018Member  | 
      
| From 4/1/2018 - 3/31/2019 | |
| Commitment And Contingencies [Line Items] | |
| Annual base rent rate per square foot | 
5.65opxs_AnnualBaseRentRatePerSquareFoot / opxs_LeasePeriodAxis = opxs_FromApril1St2018ToMarch31St2019Member  | 
      
| From 4/1/2019 - 3/31/2020 | |
| Commitment And Contingencies [Line Items] | |
| Annual base rent rate per square foot | 
5.85opxs_AnnualBaseRentRatePerSquareFoot / opxs_LeasePeriodAxis = opxs_FromApril1St2019ToMarch31St2020Member  | 
      
| From 4/1/2020 - 3/31/2021 | |
| Commitment And Contingencies [Line Items] | |
| Annual base rent rate per square foot | 
6.05opxs_AnnualBaseRentRatePerSquareFoot / opxs_LeasePeriodAxis = opxs_FromApril1St2020ToMarch31St2021Member  | 
      
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          Represents annual base rent rate, per square foot. No definition available. 
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          Represents lease improvement allowance. No definition available. 
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