v2.4.0.8
Fair Value Measurements of Financial Assets and Liabilities - Additional Information (Detail) (USD $)
9 Months Ended 12 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Sep. 30, 2014
Short-term Investments
Dec. 31, 2013
Short-term Investments
Impairment charge $ 66,000 $ 155,000 $ 0 $ 0
Maturity period of short term investments Beyond 90 days      
Stated maturity period of short term investments One year or more