Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) Project Source Method	Mar. 31, 2015 Project	Dec. 31, 2015 USD ($)
Accounting Policies [Abstract]
Number of product revenue sources | Method	2
Unbilled receivables | $	$ 61.5		$ 70.8
Number of projects | Project	9	11
Percentage of total revenues	15.00%	15.00%
Percentage of product revenues	18.00%	18.00%
Number of service revenue sources | Source	3