| **Investments - Schedule of Investments (Details) (USD $)In Thousands, unless otherwise specified** | Jun. 30, 2013 |
|-----------------------------------------------------------------------------------------------------|---------------|
| **Schedule of Available-for-sale Securities [Line Items]**                                          |          |
| Cost                                                                                                | $ 115,410     |
| Gross Unrealized Gains                                                                              | 18            |
| Gross Unrealized Losses                                                                             | 909           |
| Fair Value                                                                                          | 114,519       |
| U.S. treasury securities                                                                            |          |
| **Schedule of Available-for-sale Securities [Line Items]**                                          |          |
| Cost                                                                                                | 84,964        |
| Gross Unrealized Gains                                                                              | 18            |
| Gross Unrealized Losses                                                                             | 0             |
| Fair Value                                                                                          | 84,982        |
| Corporate debt securities                                                                           |          |
| **Schedule of Available-for-sale Securities [Line Items]**                                          |          |
| Cost                                                                                                | 30,446        |
| Gross Unrealized Gains                                                                              | 0             |
| Gross Unrealized Losses                                                                             | 909           |
| Fair Value                                                                                          | $ 29,537      |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
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| - Definition
This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.
+ References
No definition available.
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| - Definition
Amount of debt securities categorized neither as held-to-maturity nor trading.
+ References
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| - Definition
This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the gross unrealized losses for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.
+ References
No definition available.
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| X                                                                                                                                                                                 |
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