Fair Value - Change in Fair Value for All Assets and Liabilities Using Unobservable Level 3 Inputs As Determined By Level 3 Inputs (Detail) - Fair Value Measurement at Reporting Date (Level 3) [Member] $ in Thousands	3 Months Ended
Mar. 31, 2017 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 22,800
Conversion of contingent consideration to common stock	(5,227)
Change in fair value	1,227
Current portion	6,250
Long-term portion	12,550
Ending balance	$ 18,800

Fair Value - Change in Fair Value for All Assets and Liabilities Using Unobservable Level 3 Inputs As Determined By Level 3 Inputs (Detail) - Fair Value Measurement at Reporting Date (Level 3) [Member]
$ in Thousands

3 Months Ended

Mar. 31, 2017

USD ($)

Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]

Beginning balance

$ 22,800

Conversion of contingent consideration to common stock

(5,227)

1,227

6,250

12,550

$ 18,800