Fair Value Measurements - Fair Value Hierarchy of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Acquisition contingent consideration obligations	$ (1,200)
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents (money market accounts)	45,997	$ 65,136
Acquisition contingent consideration obligations	(1,984)	(1,968)
Fair value assets and liabilities measured on recurring basis, total	44,013	63,168
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents (money market accounts)	45,997	65,136
Acquisition contingent consideration obligations	0	0
Fair value assets and liabilities measured on recurring basis, total	45,997	65,136
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents (money market accounts)	0	0
Acquisition contingent consideration obligations	0	0
Fair value assets and liabilities measured on recurring basis, total	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents (money market accounts)	0	0
Acquisition contingent consideration obligations	(1,984)	(1,968)
Fair value assets and liabilities measured on recurring basis, total	$ (1,984)	$ (1,968)