Net Income Per Share - Schedule of Weighted-Average Shares Used for Net Income per Share Footnotes (Detail) - $ / shares	Aug. 01, 2020	Sep. 30, 2019	Jun. 30, 2018
Earnings Per Share Diluted
Conversion price per share		$ 211.40
Common Stock
Earnings Per Share Diluted
Conversion price per share			$ 193.65
Convertible senior notes due 2020 | Common Stock
Earnings Per Share Diluted
Conversion price per share	$ 118.13
Convertible senior notes due 2020 | Warrant
Earnings Per Share Diluted
Conversion price per share	189.00
Convertible senior notes due 2023
Earnings Per Share Diluted
Conversion price per share			$ 309.84
Convertible senior notes due 2023 | Common Stock
Earnings Per Share Diluted
Conversion price per share	193.65
Convertible senior notes due 2023 | Warrant
Earnings Per Share Diluted
Conversion price per share	309.84
Convertible senior notes due 2024 | Common Stock
Earnings Per Share Diluted
Conversion price per share	211.40
Convertible senior notes due 2024 | Warrant
Earnings Per Share Diluted
Conversion price per share	$ 338.24