Segment Reporting (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Product revenues	$ 215,714	$ 206,909
Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	100.00%	100.00%
United States
Segment Reporting Information [Line Items]
Product revenues	$ 101,740	$ 95,304
United States | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	47.00%	46.00%
South Korea
Segment Reporting Information [Line Items]
Product revenues	$ 19,096	$ 22,863
South Korea | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	9.00%	11.00%
Germany
Segment Reporting Information [Line Items]
Product revenues	$ 18,167	$ 18,840
Germany | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	9.00%
China
Segment Reporting Information [Line Items]
Product revenues	$ 17,422	$ 17,970
China | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	9.00%
Japan
Segment Reporting Information [Line Items]
Product revenues	$ 12,234	$ 11,185
Japan | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	6.00%	5.00%
Czech Republic
Segment Reporting Information [Line Items]
Product revenues	$ 9,671	$ 6,159
Czech Republic | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	5.00%	3.00%
Canada
Segment Reporting Information [Line Items]
Product revenues	$ 8,982	$ 5,485
Canada | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	4.00%	3.00%
United Kingdom
Segment Reporting Information [Line Items]
Product revenues	$ 6,667	$ 6,988
United Kingdom | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	3.00%
Mexico
Segment Reporting Information [Line Items]
Product revenues	$ 5,581	$ 5,433
Mexico | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	3.00%
Other
Segment Reporting Information [Line Items]
Product revenues	$ 16,154	$ 16,682
Other | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	7.00%	8.00%
Non U.S.
Segment Reporting Information [Line Items]
Product revenues	$ 113,974	$ 111,605
Non U.S. | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	53.00%	54.00%