Stock-based compensation - Summary of Stock Option Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding as of June 30, 2013	6,577
Granted	9
Exercised	(93)
Canceled	(340)
Options outstanding as of September 30, 2013	6,153
Options vested and expected to vest	5,983
Options exercisable	4,007
Weighted Average Exercise Price
Options outstanding	$ 5.69
Options vested and expected to vest	$ 5.65
Options exercisable	$ 4.88
Weighted Average Remaining Contractual Life
Options outstanding	6 years 0 months 29 days
Options vested and expected to vest	6 years 0 months 4 days
Options exercisable	5 years 2 months 5 days
Aggregate Intrinsic Value
Options outstanding	$ 7,827
Options vested and expected to vest	7,808
Options exercisable	$ 7,551