Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Inventory Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year		$ 371,332	$ 371,332
Charged (credited) to expenses	$ 0	0	0
Charged (credited) to other accounts		(251,023)
Deductions		(120,309)
Balance at ending of year			371,332
Accounts Receivable Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	2,315,797	4,631,593	5,131,593
Charged (credited) to expenses	0	0	0
Charged (credited) to other accounts	(29,932)	(2,315,796)
Deductions			500,000
Balance at ending of year	$ 2,345,729	$ 2,315,797	$ 4,631,593