Fair-Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	$ 21,709	$ 13,609
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as cash equivalents		213
Money-market funds classified as short-term investments	21,030	12,717
Non Current
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as restricted cash	679	679
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	21,709	13,609
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as cash equivalents		213
Money-market funds classified as short-term investments	21,030	12,717
Fair Value, Inputs, Level 1 | Non Current
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as restricted cash	$ 679	$ 679