NET LOSS PER SHARE - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	[2]	Apr. 30, 2018	Apr. 30, 2017	[2]
Earnings Per Share [Abstract]
Net loss	$ (85,674)	$ (96,835)	[1]	$ (209,792)	$ (313,506)	[1],[3]
Weighted-average shares used in computing net loss per share attributable to common stockholders—basic and diluted (in shares)	166,845,544	144,054,432		161,709,365	119,851,586
Net loss per share attributable to common stockholders—basic and diluted (in dollars per share)	$ (0.51)	$ (0.67)		$ (1.30)	$ (2.62)

[1] See Note 3 for a summary of adjustments related to the adoption of the new revenue recognition standard.

[2] See Note 3 for a summary of adjustments related to the adoption of the new revenue recognition standard.

[3] See Note 3 for a summary of adjustments related to the adoption of the new revenue recognition standard.