Schedule of Company Financial Assets and Liabilities at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	$ 14,973	$ 11,165
Available for sale securities	2,956	2,862
Contingent consideration	(4,890)	(9,043)
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	14,973	11,165
Available for sale securities	2,956	2,862
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Contingent consideration	$ (4,890)	$ (9,043)