<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>117 - Disclosure - Notes Payable</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>P01_01_2013To06_30_2013</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000844985</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>us-gaap_NotesPayableAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Notes Payable [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>posc_NotesPayableDisclosureTextBlock</ElementName><ElementPrefix>posc_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="P01_01_2013To06_30_2013" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>              &lt;table border="0" style="clear:both;width:100%; table-layout:fixed;"&gt;  &lt;tr&gt;  &lt;td&gt;&lt;/td&gt;  &lt;/tr&gt;  &lt;/table&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0pt 0px; FONT: 10pt Times New Roman, Times, Serif "&gt;  &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt; FONT-SIZE: 10pt"&gt;  &lt;table style="clear:both;WIDTH: 100%; BORDER-COLLAPSE: collapse"  border="0" cellspacing="0" cellpadding="0" width="100%"&gt;  &lt;tr&gt;  &lt;td style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; PADDING-BOTTOM: 0in; BACKGROUND-COLOR: transparent; PADDING-LEFT: 0in; WIDTH: 7%; PADDING-RIGHT: 0in; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0; PADDING-TOP: 0in"   valign="top" width="7%"&gt;  &lt;div style="clear:both;MARGIN: 0in 0in 0pt"&gt;&lt;strong&gt;&lt;font style="COLOR: black; FONT-SIZE: 10pt"&gt;13.&lt;/font&gt;&lt;/strong&gt;&lt;font style="FONT-SIZE: 10pt"&gt;&lt;/font&gt;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #f0f0f0; BORDER-LEFT: #f0f0f0; PADDING-BOTTOM: 0in; BACKGROUND-COLOR: transparent; PADDING-LEFT: 0in; WIDTH: 93%; PADDING-RIGHT: 0in; BORDER-TOP: #f0f0f0; BORDER-RIGHT: #f0f0f0; PADDING-TOP: 0in"   valign="top" width="93%"&gt;  &lt;div style="clear:both;MARGIN: 0in 0in 0pt"&gt;&lt;strong&gt;&lt;font style="COLOR: black; FONT-SIZE: 10pt"&gt;Notes Payable&lt;/font&gt;&lt;/strong&gt;&lt;font  style="FONT-SIZE: 10pt"&gt;&lt;/font&gt;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;  &lt;/table&gt;  &lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt"&gt;  &lt;font style="FONT-SIZE: 10pt"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt 0.5in"   align="justify"&gt;&lt;font style="COLOR: black; FONT-SIZE: 10pt"&gt;On  January 17, 2012, the Company assumed from MIT a note payable with  Los Alamos National Bank (&amp;#8220;LANB&amp;#8221;) in the amount of  $&lt;font style=" FONT-SIZE: 10pt"&gt;700,000&lt;/font&gt;. On February 10,  2012, MIT refinanced with LANB the principal and accrued interest  of this note payable with a promissory note of $&lt;font style=" FONT-SIZE: 10pt"&gt;708,000&lt;/font&gt;, maturing on &lt;font style=" FONT-SIZE: 10pt"&gt;April 1, 2019&lt;/font&gt;. The monthly payment to  LANB on the promissory note is $&lt;font style=" FONT-SIZE: 10pt"&gt;10,000&lt;/font&gt;, with the interest rate of &lt;font  style=" FONT-SIZE: 10pt"&gt;5.5&lt;/font&gt;% at June 30, 2013. The  promissory note is guaranteed by the Company and secured by all  assets of the Company. Total interest paid on the promissory note  was $19,000 during the six months ended June 30, 2013. The  note&amp;#8217;s outstanding amount was $&lt;font style=" FONT-SIZE: 10pt"&gt;595,000&lt;/font&gt; at&lt;/font&gt; &lt;font style="FONT-SIZE: 10pt"&gt;June 30, 2013&lt;font style="COLOR: black"&gt;.&lt;/font&gt;&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt 0.5in"   align="justify"&gt;&lt;font style="FONT-SIZE: 10pt"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt 0.5in"   align="justify"&gt;&lt;font style="FONT-SIZE: 10pt"&gt;During the six  months ended June 30, 2013, the Company received $&lt;font style=" FONT-SIZE: 10pt"&gt;935,000&lt;/font&gt; in short term notes and advances  from its CEO and CFO to help fund operations. The notes are  non-interest bearing and are included in current  maturities.&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt 0.5in"&gt;  &lt;font style="FONT-SIZE: 10pt"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt 0.5in"   align="justify"&gt;&lt;font style="FONT-SIZE: 10pt"&gt;Future maturities of  the notes payable are as follows:&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt"&gt;  &lt;strong&gt;&lt;font style="FONT-SIZE: 10pt"&gt;&amp;#160;&lt;/font&gt;&lt;/strong&gt; &lt;font  style="FONT-SIZE: 10pt"&gt;&lt;/font&gt;&lt;/div&gt;    &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;MARGIN: 0in 0in 0pt; FONT-SIZE: 10pt"&gt;  &lt;div style="clear:both; FONT-FAMILY:Times New Roman;FONT-SIZE: 10pt;TEXT-ALIGN:center; TEXT-INDENT: 0in; WIDTH: 100%"   align="center"&gt;  &lt;table style="clear:both;BORDER-BOTTOM: #9eb6ce 0px solid; BORDER-LEFT: #9eb6ce 0px solid; MARGIN: 0px:auto; WIDTH: 75%; BORDER-COLLAPSE: collapse; OVERFLOW: visible; BORDER-TOP: #9eb6ce 0px solid; BORDER-RIGHT: #9eb6ce 0px solid"   cellspacing="0" cellpadding="0" align="center"&gt;  &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="BORDER-BOTTOM: #000000 1px solid; TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;Debt maturities as of&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 1px solid; TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="16%" colspan="2"&gt;  &lt;div&gt;June 30,&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;2014&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;$&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;1,057,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;2015&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;122,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;2016&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;122,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;2017&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;122,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;2018 and thereafter&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 1px solid; TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 1px solid; TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;107,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;Total&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;1,530,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;Less: current portion&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 1px solid; TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 1px solid; TEXT-ALIGN: right; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;(1,057,000)&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ccffcc; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;    &lt;tr style="HEIGHT: 12px"&gt;  &lt;td style="TEXT-ALIGN: center; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; FONT-WEIGHT: 400"   width="57%"&gt;  &lt;div&gt;Note payable &amp;#150; noncurrent portion&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 3px double; TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;$&lt;/div&gt;  &lt;/td&gt;  &lt;td style="BORDER-BOTTOM: #000000 3px double; TEXT-ALIGN: right; FONT-STYLE: normal; PADDING-RIGHT: 5px; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: bottom; BORDER-TOP: #000000 1px solid; FONT-WEIGHT: 400"   width="15%"&gt;  &lt;div&gt;473,000&lt;/div&gt;  &lt;/td&gt;  &lt;td style="TEXT-ALIGN: left; FONT-STYLE: normal; FONT-FAMILY: Times New Roman; BACKGROUND: #ffffff; FONT-SIZE: 10pt; VERTICAL-ALIGN: middle; FONT-WEIGHT: 400"   width="1%"&gt;  &lt;div&gt;&amp;#160;&lt;/div&gt;  &lt;/td&gt;  &lt;/tr&gt;  &lt;/table&gt;  &lt;/div&gt;  &lt;/div&gt;  &lt;/div&gt;        </NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>Notes Payable Disclosure</ElementDefenition><ElementReferences>No definition available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Notes Payable</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>Notes Payable</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Notes</ReportType><RoleURI>http://www.positron.com/role/NotesPayable</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
