Components of Income Tax Provision (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Current tax provision
Federal	$ 0	$ 0	$ 0	$ 0
State	0	0	0	0
Foreign	1,787,717	7,778,520	9,214,312	12,996,602
Current Income Tax Expense (Benefit), Total	1,787,717	7,778,520	9,214,312	12,996,602
Deferred tax provision (benefit)
Federal	0	0	0	0
State	0	0	0	0
Foreign	2,699,588	1,962,539	4,523,643	(7,440,305)
Deferred Income Tax Expense (Benefit), Total	2,699,588	1,962,539	4,523,643	(7,440,305)
Income tax provision (benefit)	$ 4,487,305	$ 9,741,059	$ 13,737,955	$ 5,556,297