Fair Value Measurements (Schedule of Company Financial Assets and Liabilities at Fair Value on Recurring Basis) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	$ 27,933	$ 21,094
Available for sale securities	5,079	4,513
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	27,933	21,094
Available for sale securities	5,079	4,513
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	0	0
Available for sale securities	0	0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	0	0
Available for sale securities	$ 0	$ 0