Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 225,906	$ 217,781
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	85,377	81,469
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	27,855	26,698
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	23,367	23,227
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	11,891	11,146
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	11,714	11,540
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	3,383	3,283
Other European
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	33,989	33,568
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 28,330	$ 26,850