Concentration of Risks - Additional Information (Detail) - Customer	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Customer Concentration Risk | Total revenue
Concentration Risk [Line Items]
Concentration risk, percentage	13.00%		16.00%	14.00%
Number of customer that individually represented more than 10% of total revenue and accounts receivable	1	0	1	0
Customer Concentration Risk | Total revenue | Minimum
Concentration Risk [Line Items]
Concentration risk, percentage				10.00%
Credit Concentration Risk | Total accounts receivable
Concentration Risk [Line Items]
Concentration risk, percentage			42.00%
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		10.00%			10.00%