Fair Value (Details) Unobservable (USD $) | Mar. 31, 2015 | Dec. 31, 2014 |
In Thousands, unless otherwise specified |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable Securities, Noncurrent | $934 | $942 |
Assets, Fair Value Disclosure | 21,508 | 45,517 |
Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 20,574 | 44,575 |
Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 934 | 942 |
Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Money Market Funds [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 20,574 | 44,575 |
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 20,574 | 44,575 |
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Municipal bond | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable Securities, Noncurrent | | 942 |
Municipal bond | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable Securities, Noncurrent | 0 | 0 |
Municipal bond | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable Securities, Noncurrent | 934 | 942 |
Municipal bond | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Marketable Securities, Noncurrent | $0 | $0 |