Net Loss per Share - Anti-dilutive securities (Details) - shares	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of earnings per share	7,005,014	28,113,019
Stock options
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of earnings per share	5,860,168	3,012,176
Unvested restricted shares
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of earnings per share	1,144,846	2,215,351
Convertible Preferred Shares (Series A, B and C)
Anti-dilutive securities excluded from computation of earnings per share
Total, anti-dilutive securities excluded from computation of earnings per share		22,885,492