Industry and Geographic Information - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue, Major Customer [Line Items]
Number of reportable segments	1
Customer Concentration Risk [Member] | Non-U.S. Customers [Member]
Revenue, Major Customer [Line Items]
Accounts receivable	5.5	3.2
Customer Concentration Risk [Member] | Sales [Member]
Revenue, Major Customer [Line Items]
Percentage of risk concentration by major customer	48.00%	43.00%	42.00%
Customer Concentration Risk [Member] | Sales [Member] | Non-U.S. Customers [Member]
Revenue, Major Customer [Line Items]
Percentage of risk concentration by major customer	13.00%	13.00%	14.00%
Credit Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Accounts receivable	23.7	19.6
Credit Concentration Risk [Member] | Accounts Receivable [Member] | Minimum [Member]
Revenue, Major Customer [Line Items]
Percentage of risk concentration by major customer	10.00%	10.00%