Summary of significant accounting policies - Additional Information (Detail) lb in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($) shares	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($) shares	Dec. 31, 2014 USD ($) lb	Dec. 31, 2013 lb
Significant Accounting Policies [Line Items]
Entity Incorporation Date Of Incorporation			Jan. 11, 1991
Concentration risk, customer			two customers each accounted for 10% or more of the Companys revenues	two customers each accounted for 10% or more of the Company’s revenues
Aggregate percentage of revenue the from customers accounted for more than 10%			34.00%	26.00%
Deferred tax asset	$ 3,006,000		$ 3,006,000		$ 6,428,000
Operating loss carryforwards, limitations on use			Approximately $6,700,000 of the Company’s $7,600,000 of NOLs are subject to annual limitations of $1,300,000
Options and warrants excluded from the calculation of diluted shares | shares	1,196,343	3,676,661	75,000	80,843
Production and importation permission description			22 million pounds in 2015 and reduces by approximately 4.5 million pounds each year and ends at zero in 2020.
Production Or Importation Of Hcfc | lb					51	63
Customer
Significant Accounting Policies [Line Items]
Accounts receivable, net	$ 1,100,000	$ 2,004,000	$ 1,100,000	$ 2,004,000