Line of credit (Details) - USD ($)	3 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 29, 2018	Dec. 29, 2016
Line of Credit Facility [Line Items]
Line of Credit Facility, Fair Value of Amount Outstanding	$ 201,575	$ 165,000
Line of Credit Facility, Periodic Payment, Interest	6,581		$ 10,336
Repayments of Lines of Credit	201,575
Interest paid	35,648		$ 10,587
Accrued expenses	$ 744,164	874,421
Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 250,000
Line of Credit Facility, Current Borrowing Capacity		$ 250,000
Line of Credit Facility, Maximum Borrowing Capacity, as a Percentage of Inventory		50.00%
Debt Instrument, Closing Fee, Percent	1.00%
Line of Credit Facility, Renewal Fee, Percent	1.00%
Line of Credit Facility, Collateral Monitoring Fee, Percent	8.50%	0.70%
Line of Credit Facility, Collateral Monitoring Fee in Event of Default, Percent	1.00%
Repayments of Lines of Credit	$ 165,000
Interest paid	2,579
General and Administrative Expense	1,000
Line Of Credit Facility, Prime Plus Fee	$ 1,895
Accrued expenses		$ 28,797
Prime Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Delinquent Payments, Basis Spread on Variable Rate	5.00%
Minimum [Member] | Prime Rate [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate During Period	5.00%
Notes Payable to Banks [Member]
Line of Credit Facility [Line Items]
Notes Payable to Bank				$ 250,000
Debt Instrument, Interest Rate, Stated Percentage				5.00%
Debt Instrument, Basis Spread on Variable Rate	74.00%
Debt Instrument, Interest Rate During Period	5.74%
Line of Credit Facility, Collateral Fees, Amount	$ 250,000