Stock-Based Compensation Expense - Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Period for Recognition	1 year 6 months 30 days
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 15,158,000	$ 10,620,000	$ 8,520,000
Income tax benefit recognized related to stock-based compensation expense	4,977,000	3,482,000	2,772,000
Compensation expense capitalized	0	0	0
Product cost of revenue [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,033,000	747,000	581,000
Service cost of revenue [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	171,000	177,000	161,000
Research, development, and engineering expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,832,000	2,585,000	2,149,000
Selling, general, and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 10,122,000	$ 7,111,000	$ 5,629,000