Quarterly financial data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 40,291	$ 35,065	$ 52,001	$ 42,227	$ 47,754	$ 46,278	$ 45,253	$ 44,061	$ 169,584	$ 183,346	$ 160,239
Gross profit	17,826	17,398	23,274	18,751	20,982	20,172	20,721	20,674	77,249	82,549	81,455
Net loss	$ (12,810)	$ (13,694)	$ (11,423)	$ (9,335)	$ (7,998)	$ (9,838)	$ (6,639)	$ (10,846)	$ (47,262)	$ (35,321)	$ (23,063)
Net loss per share:
Basic and diluted (in dollars per share)	$ (0.29)	$ (0.31)	$ (0.26)	$ (0.22)	$ (0.19)	$ (0.23)	$ (0.16)	$ (0.27)