Accounts Receivable and Major Customers - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($) Customer	Dec. 31, 2015 USD ($)
Sales Revenue | Customer Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of major customers | Customer		3
Revenues, major customers	$ 26.5	$ 47.9
Concentration risk, percentage	88.00%	66.00%
Sales Revenue | Customer Concentration Risk | Major Customer 1
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenues, major customers	$ 13.9	$ 28.0
Concentration risk, percentage	46.00%	38.00%
Sales Revenue | Customer Concentration Risk | Major Customer 2
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenues, major customers	$ 12.6	$ 12.0
Concentration risk, percentage	42.00%	17.00%
Sales Revenue | Customer Concentration Risk | Major Customer 3
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenues, major customers		$ 7.9
Concentration risk, percentage		11.00%
Accounts Receivable | Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	29.00%	90.00%
Accounts receivable, major customers	$ 5.9		$ 21.1