Fair Value Measurements - Fair Value Hierarchy of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Acquisition contingent consideration obligations		$ (1,200)
Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents (money market accounts)	$ 33,977	65,010
Acquisition contingent consideration obligations		(1,968)
Fair value assets and liabilities measured on recurring basis, total	33,977	63,042
Recurring | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents (money market accounts)	33,977	65,010
Acquisition contingent consideration obligations		0
Fair value assets and liabilities measured on recurring basis, total	33,977	65,010
Recurring | 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
Fair value assets and liabilities measured on recurring basis, total	0	0
Recurring | 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		(1,968)
Fair value assets and liabilities measured on recurring basis, total	$ 0	$ (1,968)