Schedule of Company Financial Assets and Liabilities at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	$ 8,681	$ 11,899
Available for sale securities	2,908	2,785
Contingent consideration	(9,870)	(3,000)
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money market investment	8,681	11,899
Available for sale securities	2,908	2,785
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Contingent consideration	$ (9,870)	$ (3,000)