Line of credit (Details) - USD ($)	6 Months Ended
	Dec. 31, 2016	Dec. 29, 2016	Jun. 30, 2016
Line of Credit Facility [Line Items]
Line of credit outstanding	$ 247,000		$ 0
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)	8.75%
Fiscal period used to compute interest	360 days
Closing fee (as a percent)	1.00%
Renewal fee (as a percent)	1.00%
Collateral monitoring fee (as a percent)	0.70%
Collateral monitoring fee in event of default (as a percent)	1.00%
Overpayment of transaction fee	$ 3,000
Line of credit outstanding	$ 247,000
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)	3.75%
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%