Cash Equivalents and Investments - Additional Information (Detail) - USD ($) $ in Millions |
9 Months Ended | |
---|---|---|
Sep. 30, 2016 |
Dec. 31, 2015 |
|
Cash Equivalents And Investments [Line Items] | ||
Cash equivalents | $ 8.1 | $ 13.9 |
Cash Equivalents [Member] | ||
Cash Equivalents And Investments [Line Items] | ||
Cash equivalents | $ 8.1 | $ 13.9 |
Maximum [Member] | ||
Cash Equivalents And Investments [Line Items] | ||
Long-term investments maturity period, in years | 7 years | |
Short-Term investments maturity period, in years | 1 year | |
Minimum [Member] | ||
Cash Equivalents And Investments [Line Items] | ||
Long-term investments maturity period, in years | 1 year |