Segment Reporting (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Product revenues	$ 223,818	$ 206,012	$ 644,168	$ 606,132
Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	100.00%	100.00%	100.00%	100.00%
United States
Segment Reporting Information [Line Items]
Product revenues	$ 99,833	$ 96,680	$ 293,904	$ 270,597
United States | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	45.00%	47.00%	45.00%	45.00%
China
Segment Reporting Information [Line Items]
Product revenues	$ 24,092	$ 17,557	$ 58,452	$ 50,850
China | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	11.00%	9.00%	9.00%	8.00%
Germany
Segment Reporting Information [Line Items]
Product revenues	$ 18,449	$ 22,529	$ 56,088	$ 70,491
Germany | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	11.00%	9.00%	12.00%
South Korea
Segment Reporting Information [Line Items]
Product revenues	$ 18,271	$ 21,339	$ 62,347	$ 67,293
South Korea | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	10.00%	10.00%	11.00%
Mexico
Segment Reporting Information [Line Items]
Product revenues	$ 12,441	$ 4,991	$ 23,200	$ 14,752
Mexico | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	6.00%	2.00%	4.00%	2.00%
Japan
Segment Reporting Information [Line Items]
Product revenues	$ 10,965	$ 11,970	$ 33,482	$ 34,291
Japan | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	5.00%	6.00%	5.00%	6.00%
Czech Republic
Segment Reporting Information [Line Items]
Product revenues	$ 7,522	$ 6,457	$ 20,757	$ 19,398
Czech Republic | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	3.00%	3.00%	3.00%
Canada
Segment Reporting Information [Line Items]
Product revenues	$ 7,353	$ 4,811	$ 18,928	$ 12,542
Canada | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	2.00%	3.00%	2.00%
United Kingdom
Segment Reporting Information [Line Items]
Product revenues	$ 6,199	$ 5,363	$ 19,825	$ 18,162
United Kingdom | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	3.00%	3.00%	3.00%
Other
Segment Reporting Information [Line Items]
Product revenues	$ 18,693	$ 14,315	$ 57,185	$ 47,756
Other | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	7.00%	9.00%	8.00%
Non U.S.
Segment Reporting Information [Line Items]
Product revenues	$ 123,985	$ 109,332	$ 350,264	$ 335,535
Non U.S. | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	55.00%	53.00%	55.00%	55.00%