Concentration of Risks - Additional Information (Detail) - Customer	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Customer Concentration Risk | Total revenue
Concentration Risk [Line Items]
Number of customer that individually represented more than 10% of total revenue and accounts receivable	1	0
Customer Concentration Risk | Total revenue | Minimum
Concentration Risk [Line Items]
Concentration risk, percentage	15.00%
Credit Concentration Risk | Total accounts receivable
Concentration Risk [Line Items]
Number of customer that individually represented more than 10% of total revenue and accounts receivable	1	0
Credit Concentration Risk | Total accounts receivable | Minimum
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	10.00%