Line of credit (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017	Jun. 30, 2017	Dec. 29, 2016
Line of Credit Facility [Line Items]
Line of credit outstanding	$ 225,000			$ 250,000
Line of Credit Facility, Periodic Payment, Interest	10,336	$ 0
Interest Expense	$ 33,448	$ 10,313
Line of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity					$ 250,000
Maximum borrowing capacity (as a percentage of inventory					50.00%
Current annual interest rate (as a percent)	9.25%
Fiscal period used to compute interest	360 days
Collateral monitoring fee (as a percent)	8.50%		0.70%
Collateral monitoring fee in event of default (as a percent)			1.00%
Line of credit outstanding	$ 225,000			$ 250,000
Prime Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	5.00%
Variable rate basis (as a percent)	4.25%
Basis spread on variable rate if delinquent (as a percent)	10.00%
Minimum [Member] | Prime Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Current annual interest rate (as a percent)	5.00%