v2.4.0.8

Fair Value of Financial Instruments (Fair Value Hierarchy) (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2013 | Dec. 31, 2012
--- | --- | ---
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | $ 105,133 | $ 94,843
Level 1 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 | 0
Level 2 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 105,133 | 94,843
Level 3 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 | 0
Fair Value | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 105,133 | 94,843
Commercial paper |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 47,488 | 32,376
Commercial paper | Level 1 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 | 0
Commercial paper | Level 2 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 47,488 | 32,376
Commercial paper | Level 3 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 | 0
Commercial paper | Fair Value | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 47,488 | 32,376
U.S. government agencies |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 18,837 | 62,467
U.S. government agencies | Level 1 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 | 0
U.S. government agencies | Level 2 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 18,837 | 62,467
U.S. government agencies | Level 3 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 | 0
U.S. government agencies | Fair Value | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 18,837 | 62,467
Municipal bonds |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 1,128 |
Municipal bonds | Level 1 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 |
Municipal bonds | Level 2 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 1,128 |
Municipal bonds | Level 3 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 |
Municipal bonds | Fair Value | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 1,128 |
Corporate bonds |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 32,179 |
Corporate bonds | Level 1 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 |
Corporate bonds | Level 2 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 32,179 |
Corporate bonds | Level 3 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 |
Corporate bonds | Fair Value | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 32,179 |
Asset-backed securities |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 5,501 |
Asset-backed securities | Level 1 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 |
Asset-backed securities | Level 2 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 5,501 |
Asset-backed securities | Level 3 | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | 0 |
Asset-backed securities | Fair Value | Recurring Basis |  |
Assets, Fair Value Disclosure [Abstract] |  |
Available-for-sale securities, fair value | $ 5,501 |

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 + Details
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