Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset measured and recognized at fair value on recurring basis		$ 0	$ 0
Liability measured and recognized at fair value on non-recurring basis		0	0
Fair Value, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earn-out liability		0	0	$ 3,510,000
SPA
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earn-out liability				$ 3,510,000
Earn-out Consideration liability settled	$ 3,510,000
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalent at recurring basis		0	0
Fair Value Measurements, Non-recurring | Fair Value, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Privately-held investments measured at fair value		$ 300,000	$ 300,000