Subsequent Events - Open Market Sale Agreement (Details) - Common Stock - USD ($) $ / shares in Units, $ in Millions		3 Months Ended				9 Months Ended	13 Months Ended
	Aug. 01, 2023	Jul. 31, 2023	Apr. 30, 2023	Jul. 31, 2022	Apr. 30, 2022	Jul. 31, 2023	Jul. 31, 2023
Subsequent Event [Line Items]
Stock issued during period shares new issues		37,931,204	949,438	7,814,115	19,896,904
Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC
Subsequent Event [Line Items]
Average sale price per share							$ 2.67
Gross proceeds from issuance of common stock						$ 88.0
Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC | 2022 Open Market Sale Agreement
Subsequent Event [Line Items]
Shares sold during the period		41,300,000				42,300,000	60,800,000
Stock issued during period shares new issues		37,900,000				38,900,000	57,400,000
Average sale price per share		$ 2.24				$ 2.26	$ 2.67
Gross proceeds from issuance of common stock		$ 85.1				$ 88.0	$ 155.0
Net proceeds from issuance of common stock		83.3				85.9	151.2
Payments of commissions		$ 1.8				$ 2.1	$ 3.8
Jefferies LLC, B. Riley Securities, Inc., Barclays Capital Inc., BMO Capital Markets Corp., BofA Securities, Inc., Canacord Genuity LLC, Citigroup Global Markets Inc., J.P. Morgan Securities LLC and Loop Capital Markets LLC | Subsequent Event [Member] | 2022 Open Market Sale Agreement
Subsequent Event [Line Items]
Shares sold during the period	2,000,000.0
Average sale price per share	$ 2.14
Gross proceeds from issuance of common stock	$ 4.3
Net proceeds from issuance of common stock	4.2
Payments of commissions	$ 0.1