Summary of significant accounting policies - Additional Information (Detail)	6 Months Ended					6 Months Ended
	Jun. 30, 2013 USD ($)	Jun. 30, 2012	Dec. 31, 2012 USD ($)	Jun. 30, 2013 Customer USD ($)	Jun. 30, 2012 Customer USD ($)	Jun. 30, 2014 Subsequent Event GBP (£)	Jun. 30, 2013 Subsequent Event GBP (£)
Significant Accounting Policies [Line Items]
Entity Incorporation Date Of Incorporation	Jan. 11, 1991
Number of customer accounted for approximately 10% or more of total revenues	2	3
Aggregate percentage of revenue the from customers accounted for more then 10%	29.00%	40.00%
Deferred tax asset	$ 3,391,000		$ 3,888,000
Operating loss carryforwards, limitations on use	Companys NOLs are subject to annual limitations of $1,300,000
Options and warrants excluded from the calculation of diluted shares	50,000	0
Production and importation permission from government agency, amount						51,000,000	63,000,000
Accounts receivable, net				$ 1,800,000	$ 3,300,000