Stockholders' equity - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Number of shares
Options outstanding (in shares)	3,409
Granted (in shares)	55
Exercised (in shares)	(1,351)
Canceled or expired (in shares)	(475)
Options outstanding (in shares)	1,638	3,409
Options vested and expected to vest (in shares)	1,620
Options exercisable (in shares)	1,432
Weighted average exercise price per share
Options outstanding - Weighted average exercise price - Beginning balance (in dollars per share)	$ 6.49
Granted - Weighted average exercise price (in dollars per share)	4.92
Exercised - Weighted average exercise price (in dollars per share)	6.27
Canceled or expired - Weighted average exercise price (in dollars per share)	6.78
Options outstanding - Weighted average exercise price - Ending balance (in dollars per share)	6.55	$ 6.49
Options vested and expected to vest - Weighted average exercise price (in dollars per share)	6.56
Options exercisable - Weighted average exercise price (in dollars per share)	$ 6.74
Weighted average remaining contractual life (years)
Options outstanding - Weighted average remaining contractual life	5 years 2 months 1 day
Options vested and expected to vest - Weighted average remaining contractual life	5 years 1 month 20 days
Options exercisable - Weighted average remaining contractual life	4 years 9 months 14 days
Aggregate intrinsic value
Options outstanding - Aggregate intrinsic value	$ 209
Options vested and expected to vest - Aggregate intrinsic value	201
Options exercisable - Aggregate intrinsic value	128
Cash received from exercises of stock options	8,432	$ 8,853	$ 681
Total intrinsic value of stock options exercised	$ 5,300	$ 1,100	$ 227