CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (92.2)	$ (59.6)
Other comprehensive income (loss), net of tax:
Change in unrealized gains (losses) on investments	(1.3)	2.7
Change in unrealized gains (losses) on cash flow hedges	(6.0)	0.4
Other comprehensive income (loss)	(7.3)	3.1
Comprehensive loss	$ (99.5)	$ (56.5)