Segment Reporting (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Product revenues	$ 206,909	$ 193,938
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	95,304	85,067
United States | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	46.00%	44.00%
South Korea
Segment Reporting Information [Line Items]
Product revenues	22,863	21,915
South Korea | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	11.00%	11.00%
Germany
Segment Reporting Information [Line Items]
Product revenues	18,840	22,476
Germany | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	9.00%	12.00%
China
Segment Reporting Information [Line Items]
Product revenues	17,970	15,944
China | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	9.00%	8.00%
Japan
Segment Reporting Information [Line Items]
Product revenues	11,185	10,465
Japan | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	5.00%	6.00%
United Kingdom
Segment Reporting Information [Line Items]
Product revenues	6,988	6,600
United Kingdom | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	3.00%
Czech Republic
Segment Reporting Information [Line Items]
Product revenues	6,159	6,086
Czech Republic | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	3.00%
Canada
Segment Reporting Information [Line Items]
Product revenues	5,485	3,162
Canada | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	2.00%
Mexico
Segment Reporting Information [Line Items]
Product revenues	5,433	4,703
Mexico | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	2.00%
Other
Segment Reporting Information [Line Items]
Product revenues	16,682	17,520
Other | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	9.00%
Non U.S.
Segment Reporting Information [Line Items]
Product revenues	$ 111,605	$ 108,871
Non U.S. | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	54.00%	56.00%