Fair Value Measurements (Details) (USD $)
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Mar. 31, 2013
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Dec. 31, 2012
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
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Available-for-sale Securities |
$ 92,000
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$ 92,000
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Carrying (Reported) Amount, Fair Value Disclosure [Member]
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
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Cash and Cash Equivalents, Fair Value Disclosure |
53,333,000
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Marketable Securities, Fair Value Disclosure |
3,788,000
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Estimate of Fair Value, Fair Value Disclosure [Member]
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
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Cash and Cash Equivalents, Fair Value Disclosure |
53,333,000
|
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Fair Value, Inputs, Level 1 [Member]
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
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Cash and Cash Equivalents, Fair Value Disclosure |
53,333,000
|
|
Marketable Securities, Fair Value Disclosure |
3,788,000
|
|
Money Market Funds [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
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Marketable Securities, Fair Value Disclosure |
48,000
|
|
Money Market Funds [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
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|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Marketable Securities, Fair Value Disclosure |
48,000
|
|
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Marketable Securities, Fair Value Disclosure |
48,000
|
|
Mutual Funds [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
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|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
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Marketable Securities, Fair Value Disclosure |
44,000
|
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Mutual Funds [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Marketable Securities, Fair Value Disclosure |
44,000
|
|
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Marketable Securities, Fair Value Disclosure |
44,000
|
|
US Treasury Securities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
|
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
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Marketable Securities, Fair Value Disclosure |
2,434,000
|
|
US Treasury Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
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Marketable Securities, Fair Value Disclosure |
2,434,000
|
|
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Marketable Securities, Fair Value Disclosure |
2,434,000
|
|
US Government Agencies Securities [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
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Marketable Securities, Fair Value Disclosure |
1,262,000
|
|
US Government Agencies Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
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|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
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Marketable Securities, Fair Value Disclosure |
1,262,000
|
|
US Government Agencies Securities [Member] | Fair Value, Inputs, Level 1 [Member]
|
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Marketable Securities, Fair Value Disclosure |
1,262,000
|
|
Cash [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
|
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
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Cash and Cash Equivalents, Fair Value Disclosure |
11,505,000
|
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Cash [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Cash and Cash Equivalents, Fair Value Disclosure |
11,505,000
|
|
Cash [Member] | Fair Value, Inputs, Level 1 [Member]
|
|
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Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Cash and Cash Equivalents, Fair Value Disclosure |
11,505,000
|
|
Money Market Funds [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
|
|
|
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Cash and Cash Equivalents, Fair Value Disclosure |
41,828,000
|
|
Money Market Funds [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
|
|
|
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Cash and Cash Equivalents, Fair Value Disclosure |
41,828,000
|
|
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
|
|
|
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |
|
|
Cash and Cash Equivalents, Fair Value Disclosure |
$ 41,828,000
|
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