Net Loss Per Share - Additional Information (Details)	3 Months Ended
	Apr. 30, 2020 shares $ / shares
Class of Stock [Line Items]
Shares issuable upon conversion (in shares) | shares	6,800,000
Average market price (in dollars per share) | $ / shares	$ 146.81
Class A Common Stock
Class of Stock [Line Items]
Number of votes per share | shares	1
Class B Common Stock
Class of Stock [Line Items]
Number of votes per share | shares	10
Convertible Debt | 2024 Notes
Class of Stock [Line Items]
Initial conversion price (in dollars per share) | $ / shares	$ 68.15
Convertible Debt | 2026 Notes
Class of Stock [Line Items]
Initial conversion price (in dollars per share) | $ / shares	$ 211.20