| Deferred revenue (Details) - USD ($) | Dec. 31, 2015 | Dec. 31, 2014 | 
|---|---|---|
| Deferred Revenue Details | ||
| Deferred revenue | $ 866 | $ 0 | 
| X | ||||||||||
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- References No definition available. 
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| X | ||||||||||
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- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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