Segment Reporting (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Product revenues	$ 213,441	$ 206,182	$ 420,350	$ 400,120
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	$ 98,767	$ 88,850	$ 194,071	$ 173,917
United States | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	46.00%	43.00%	46.00%	43.00%
South Korea
Segment Reporting Information [Line Items]
Product revenues	$ 21,213	$ 24,039	$ 44,076	$ 45,954
South Korea | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	10.00%	12.00%	10.00%	11.00%
Germany
Segment Reporting Information [Line Items]
Product revenues	$ 18,799	$ 25,486	$ 37,639	$ 47,962
Germany | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	9.00%	12.00%	9.00%	12.00%
China
Segment Reporting Information [Line Items]
Product revenues	$ 16,390	$ 17,349	$ 34,360	$ 33,293
China | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	8.00%	8.00%	8.00%	8.00%
Japan
Segment Reporting Information [Line Items]
Product revenues	$ 11,332	$ 11,856	$ 22,517	$ 22,321
Japan | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	5.00%	7.00%	5.00%	6.00%
Czech Republic
Segment Reporting Information [Line Items]
Product revenues	$ 7,076	$ 6,855	$ 13,235	$ 12,941
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%
United Kingdom
Segment Reporting Information [Line Items]
Product revenues	$ 6,638	$ 6,199	$ 13,626	$ 12,799
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%
Malaysia
Segment Reporting Information [Line Items]
Product revenues	$ 6,108
Malaysia | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	3.00%	0.00%
Canada
Segment Reporting Information [Line Items]
Product revenues	$ 6,090	$ 4,569	$ 11,575	$ 7,731
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%
Mexico
Segment Reporting Information [Line Items]
Product revenues			$ 10,759	$ 9,761
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	$ 21,028	$ 20,979	$ 38,492	$ 33,441
Other | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	10.00%	10.00%	10.00%	10.00%
Non U.S.
Segment Reporting Information [Line Items]
Product revenues	$ 114,674	$ 117,332	$ 226,279	$ 226,203
Non U.S. | Sales Revenue, Net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Total product revenues in percentage	54.00%	57.00%	54.00%	57.00%