Investments (Details) (USD $)	6 Months Ended
Jun. 30, 2011
Contract maturity of available-for-sale securities
One year or less (as a percent)	76.00%
After one year but within two years (as a percent)	20.00%
After two years but within three years (as a percent)	4.00%
Total (as a percent)	100.00%
Percentage of short-term instruments (as a percent)	96.00%
Available-for-sale securities with maturities of less than two years	2
Ownership interests in private and public companies
Entity's cost method equity investments ownership percentage, less than (as a percent)	20.00%
Number of privately-held companies in which the entity has an equity ownership interest of less than 20%	5
Number of publicly-held companies in which the entity has an equity ownership interest of less than 20%	2
Recognized loss on investments	$ 285,000
Valuation allowance related to investment in Excaliard	$ 359,000

The percentage of available-for-sale debt securities that mature beyond one year but within two years of the balance sheet date.

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- Definition

The percentage of available-for-sale debt securities that mature beyond two years but within three years of the balance sheet date.

+ Details

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- Definition

The aggregate percentage of all available-for-sale debt securities, regardless of maturity.

+ Details

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- Definition

The percentage of available-for-sale debt securities that mature within one year of the balance sheet date.

+ Details

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- Definition

The percentage of available-for-sale debt securities having short span of life as of the balance sheet date.

+ Details

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- Definition

Represents the maturity period for available-for-sale securities.

+ Details

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- Definition

The entity's cost method equity investments ownership percentage is less than this percentage.

+ Details

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- Details

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- Definition

Number of privately-held companies, in which the entity has an equity ownership interest of less than 20%, with which it conducts business. These are accounted for under the cost method.

+ Details

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- Definition

Number of publicly-held companies, in which the entity has an equity ownership interest of less than 20%, with which it conducts business.

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- Definition

For investments in debt and equity securities accounted for at cost, the excess of the carrying amount over net sale proceeds of investments disposed of during the period and any losses recognized thereon for impairments of other than a temporary nature.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.9(a))
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, acquired in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 09
-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690

+ Details

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