|
Fair Value Measurements - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
Jun. 30, 2014
|
Dec. 31, 2013
|
|---|---|---|
| Fair Value Disclosures [Abstract] | ||
| Money market fund investments | $ 23.3 | $ 44.7 |
| Certificates of deposit | 1.0 | 0.5 |
| 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 |