Fair Value Measurements - Summary of the financial instruments of the company at fair value (Details) (USD $) | Mar. 31, 2014 | Dec. 31, 2013 |
In Thousands, unless otherwise specified |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Carrying value | $21,697 | $21,710 |
Money Market Funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Carrying value | 721 | 655 |
Fair Value, Inputs, Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 721 | 655 |
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 721 | 655 |
Fair Value, Inputs, Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 20,964 | 21,037 |
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 0 | 0 |
Corporate Bond Securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Carrying value | 7,271 | 7,305 |
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 0 | 0 |
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 7,270 | 7,303 |
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 0 | 0 |
Certificates of Deposit [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Carrying value | 13,705 | 13,750 |
Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 0 | 0 |
Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | 13,694 | 13,734 |
Certificates of Deposit [Member] | Fair Value, Inputs, Level 3 [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fair market value | $0 | $0 |