Summary of Total Revenues from External Customers and Collaborative Partners by Geographic Region (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenue from External Customer [Line Items]
Total revenues	$ 303,745	$ 236,736
United States
Revenue from External Customer [Line Items]
Total revenues	132,485	109,146
Europe
Revenue from External Customer [Line Items]
Total revenues	66,019	59,710
Latin America
Revenue from External Customer [Line Items]
Total revenues	37,263	18,379
Rest of World
Revenue from External Customer [Line Items]
Total revenues	$ 67,978	$ 49,501