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Fair Value of Financial Instruments - Securities with Unrealized Losses (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2016 USD ($) item | Dec. 31, 2015 USD ($) item
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract] |  |
Available For Sale Securities, Number of Maturity Groups | item | 2 | 2
Due within 1 year,Cost | $ 1,002 | $ 14,614
Due within 1 year,Unrealized Losses |  | (16)
Due within 1 year, Fair Value | $ 1,002 | 14,598
Short-term investments. |  |
Estimated fair values of available-for-sale securities with unrealized losses |  |
Cost |  | 8,171
Unrealized Losses |  | 16
Fair value |  | 8,155
Short-term investments. | Corporate notes |  |
Estimated fair values of available-for-sale securities with unrealized losses |  |
Cost |  | 8,171
Unrealized Losses |  | 16
Fair value |  | $ 8,155

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- Definition Represents the cost of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References No definition available. + Details
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- Definition Represents the gross unrealized losses for available-for-sale debt securities, maturing in the next rolling twelve months following the latest balance sheet presented. + References No definition available. + Details
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- Definition Represents the number of maturity groups for available-for-sale securities. + References No definition available. + Details
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- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 + Details
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- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
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- Definition Amount after adjustments of available-for-sale debt securities at cost, maturing in the next rolling twelve months following the latest balance sheet. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments and fair value hedge accounting adjustments. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References No definition available. + Details
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- Definition Fair value of available-for-sale debt securities maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References No definition available. + Details
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