Summary of business and significant accounting policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 35,351	$ 64,496	$ 73,875	$ 66,629	$ 51,703	$ 48,540	$ 50,160	$ 46,252	$ 240,351	$ 196,655	$ 191,234
Product
Disaggregation of Revenue [Line Items]
Total revenue									191,253	168,619	163,599
Services
Disaggregation of Revenue [Line Items]
Total revenue									49,098	28,036	27,635
Transferred at point in time | On-board automotive navigation solutions
Disaggregation of Revenue [Line Items]
Total revenue									191,253	168,619	163,599
Transferred over time | Brought-in automotive navigation solutions
Disaggregation of Revenue [Line Items]
Total revenue									36,406	17,161	14,209
Transferred over time | Automotive maintenance and support
Disaggregation of Revenue [Line Items]
Total revenue									3,181	1,055	34
Transferred over time | Mobile navigation services
Disaggregation of Revenue [Line Items]
Total revenue									$ 9,511	$ 9,820	$ 13,392