Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($) Project Source Method	Dec. 31, 2015 USD ($) Project	Dec. 31, 2014 USD ($)
Accounting Policies [Abstract]
Inventory reserves	$ (45,648,000)	$ (39,247,000)
Impairments of long-lived assets	$ 0	0	$ 0
Number of product revenue sources | Method	2
Unbilled receivables	$ 56,800,000	$ 70,800,000
Number of projects | Project	10	14
Percentage of total revenues	14.00%	16.00%
Percentage of product revenues	17.00%	19.00%
Number of service revenue sources | Source	3
Gains/(losses) in foreign currency exchange transactions	$ (25,600,000)	$ (3,900,000)	$ (3,400,000)