Fair Value Measurements - Schedule of reconciliation of opening and closing balances for fair value measurements categorized within Level 3 (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Contingent Purchase Price Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 3,686	$ 0
Additions	1,300	3,686
Payments	(152)
Accretion expense	887
Valuation (gain) loss for the period	(118)	0
Ending balance	5,603	3,686
Convertible Notes Derivative Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	33,337	23,436
Additions	0	0
Payments	0
Accretion expense	0
Valuation (gain) loss for the period	(5,805)	9,901
Ending balance	$ 27,532	$ 33,337