Subsequent event (unaudited) - Schedule of Pro Forma Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019		Jun. 30, 2018	[2]	Jun. 30, 2017	[2]
Pro forma results of operations
Net loss	$ (12,856)	$ (7,481)	$ (4,581)	$ (7,570)	$ (7,465)	$ (14,457)	$ (8,394)	$ (10,518)	$ (32,488)	[1]	$ (40,834)	[1]	$ (29,536)	[1]
Pro forma loss per share
Net loss per share, basic and diluted (in dollars per share)	$ (0.28)	$ (0.16)	$ (0.10)	$ (0.17)	$ (0.17)	$ (0.32)	$ (0.19)	$ (0.24)	$ (0.71)		$ (0.92)		$ (0.68)
Pro Forma
Pro forma results of operations
Loss from continuing operations									$ (25,556)
Net loss									$ (32,488)
Pro forma loss per share
Continuing operations (in dollars per share)									$ (0.56)
Net loss per share, basic and diluted (in dollars per share)									$ (0.71)

[1] See Note 1 for a summary of adjustments. The cumulative effect adjustment to Accumulated Deficit and Total Stockholders' Equity related to the adoption of ASU No. 2014-09 (Topic 606) as of June 30, 2016 was $11.8 million.

[2] See Note 1 for a summary of adjustments.