| **Fair Value Measurements (Tables)**                               | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
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| **Fair Value Measurements [Abstract]**                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Assets measured at fair value on recurring basis                   | The following tables present our money market funds and auction rate securities measured at fair value on a recurring basis as of September 30, 2012 and December 31, 2011, classified by valuation hierarchy: Fair Value Measurements at September 30, 2012Investment TypeBalance atSeptember 30, 2012Quoted Prices in Active Markets for Identical Assets(Level 1)Significant Other Observable Inputs(Level 2)Significant Unobservable Inputs(Level 3)Money market funds$36,211$36,211$-$-Auction rate securities 3,240 - - 3,240Total$39,451$36,211$-$3,240 Fair Value Measurements at December 31, 2011Investment TypeBalance atDecember 31, 2011Quoted Prices in Active Markets for Identical Assets(Level 1)Significant Other Observable Inputs(Level 2)Significant Unobservable Inputs(Level 3)Money market funds$64,068$64,068$-$-Auction rate securities  3,332 - - 3,332Total$67,400$64,068$-$3,332                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Summary of activities in financial instruments with Level 3 inputs | For our financial instruments with significant Level 3 inputs (all of which are auction rate securities), the following table summarizes the activities for the three and nine months ended September 30, 2012 and 2011:  Fair Value Measurements Using SignificantUnobservable Inputs(Level 3)For the Three Months Ended September 30, Description 2012  2011 Balance at beginning of period $3,240  $3,516 Transfers into Level 3  -   - Transfers out of Level 3  -   - Total gains (losses)        Included in net loss  -   - Included in other comprehensive loss  -   8 Settlements at par  -   (100)Balance at end of period $3,240  $3,424 Changes in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at the end of the reporting period $-  $-   Fair Value Measurements Using SignificantUnobservable Inputs(Level 3)For the Nine Months Ended September 30, Description 2012  2011 Balance at beginning of period $3,332  $3,608 Transfers into Level 3  -   - Transfers out of Level 3  -   - Total gains (losses)        Included in net loss  -   - Included in other comprehensive loss  8   16 Settlements at par  (100)  (200)Balance at end of period $3,240  $3,424 Changes in unrealized gains or losses for the period included in earnings (or changes in net assets) for assets held at the end of the reporting period $-  $-  |

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| - Definition
Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 6 -Footnote 4 -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.Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -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.Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19190-110258Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258
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| - Definition
Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.
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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19279-110258Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -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.
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