Significant Customers - Additional Information (Detail) - Customer	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Revenue, Major Customer [Line Items]
Number of significant customer	4	2	1	2
Number of other customers accounted for more than 10% of revenue	0		0
Trade receivables	10.00%		10.00%
Accounts receivable	67.00%		67.00%		50.00%
Customer One [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Revenue	16.00%	29.00%	23.00%	24.00%
Customer Two [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Revenue	15.00%	10.00%		10.00%
Customer Three [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Revenue	14.00%
Customer Four [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Revenue	11.00%
All Other Customers [Member] | Customer Concentration Risk [Member] | Maximum [Member]
Revenue, Major Customer [Line Items]
Revenue			10.00%	10.00%