Industry segment and geographic information - Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue	$ 43,186	$ 42,286	$ 39,780	$ 34,987	$ 34,385	$ 34,471	$ 37,161	$ 44,296	$ 160,239	$ 150,313	$ 191,800
Cost of revenue									78,784	60,841	69,113
Gross profit	$ 20,734	$ 21,447	$ 20,247	$ 19,027	$ 19,006	$ 20,232	$ 21,987	$ 28,247	$ 81,455	$ 89,472	$ 122,687
Gross margin (as a percent)									51.00%	60.00%	64.00%
Automotive
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue									$ 103,100	$ 75,153	$ 71,476
Cost of revenue									56,319	37,135	38,247
Gross profit									$ 46,781	$ 38,018	$ 33,229
Gross margin (as a percent)									45.00%	51.00%	46.00%
Advertising
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue									$ 17,941	$ 11,699	$ 3,935
Cost of revenue									11,710	7,012	2,506
Gross profit									$ 6,231	$ 4,687	$ 1,429
Gross margin (as a percent)									35.00%	40.00%	36.00%
Mobile Navigation
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenue									$ 39,198	$ 63,461	$ 116,389
Cost of revenue									10,755	16,694	28,360
Gross profit									$ 28,443	$ 46,767	$ 88,029
Gross margin (as a percent)									73.00%	74.00%	76.00%