|
Fair Value Measurements - Additional Information (Detail) (USD $)
|
Sep. 30, 2014
|
Dec. 31, 2013
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|---|---|---|
| Fair Value Disclosures [Abstract] | ||
| Money market fund investments | $ 19,100,000 | $ 44,700,000 |
| Certificates of deposit | 500,000 | 500,000 |
| Fair value of assets transfers between Level 1 and Level 2 | 0 | |
| Fair value of liabilities transfers between Level 1 and Level 2 | 0 | |
| Short-term investments that were classified as Level 3 | 0 | 0 |
| Long-term investments that were classified as Level 3 | $ 0 | $ 0 |