Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 Source Project Method	Mar. 31, 2013 Project	Dec. 31, 2013
Accounting Policies [Abstract]
Number of product revenue sources	2
Unbilled receivables	$ 60.0		$ 52.9
Number of projects	15	14
Percentage of total revenues	12.00%	19.00%
Percentage of product revenues	14.00%	22.00%
Number of service revenue sources	3