Summary of business and significant accounting policies - Concentration of Risk and Significant Customers (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2019
Ford Motor Company | Sales Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	48.00%	59.00%	46.00%	64.00%
Ford Motor Company | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			43.00%		33.00%
GM | Sales Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	39.00%	21.00%	31.00%	19.00%
GM | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			37.00%		15.00%
Grab | Sales Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%		10.00%
Xevo Inc | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			10.00%		29.00%