Segment Reporting (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Product revenues	$ 232,625	$ 223,818	$ 681,059	$ 644,168
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	$ 117,815	$ 99,833	$ 332,693	$ 293,904
United States | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	51.00%	45.00%	49.00%	45.00%
South Korea
Segment Reporting Information [Line Items]
Product revenues	$ 16,295	$ 18,271	$ 56,443	$ 62,347
South Korea | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	7.00%	8.00%	8.00%	10.00%
China
Segment Reporting Information [Line Items]
Product revenues	$ 21,573	$ 24,092	$ 57,983	$ 58,452
China | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	9.00%	11.00%	9.00%	9.00%
Germany
Segment Reporting Information [Line Items]
Product revenues	$ 17,670	$ 18,449	$ 54,261	$ 56,088
Germany | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	8.00%	8.00%	9.00%
Czech Republic
Segment Reporting Information [Line Items]
Product revenues	$ 9,302	$ 7,522	$ 29,264	$ 20,757
Czech Republic | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	4.00%	3.00%	4.00%	3.00%
Japan
Segment Reporting Information [Line Items]
Product revenues	$ 10,532	$ 10,965	$ 32,545	$ 33,482
Japan | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	4.00%	5.00%	5.00%	5.00%
Canada
Segment Reporting Information [Line Items]
Product revenues	$ 9,440	$ 7,353	$ 28,513	$ 18,928
Canada | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	4.00%	3.00%	4.00%	3.00%
United Kingdom
Segment Reporting Information [Line Items]
Product revenues	$ 6,824	$ 6,199	$ 20,561	$ 19,825
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%
Mexico
Segment Reporting Information [Line Items]
Product revenues	$ 5,288	$ 12,441	$ 16,848	$ 23,200
Mexico | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	2.00%	6.00%	2.00%	4.00%
Other
Segment Reporting Information [Line Items]
Product revenues	$ 17,886	$ 18,693	$ 51,948	$ 57,185
Other | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	8.00%	8.00%	9.00%
Non U.S.
Segment Reporting Information [Line Items]
Product revenues	$ 114,810	$ 123,985	$ 348,366	$ 350,264
Non U.S. | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	49.00%	55.00%	51.00%	55.00%