Consolidated Balance Sheets (Parenthetical) - $ / shares	Jan. 31, 2020	Jan. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares outstanding (in shares)	181,254,000	169,303,000
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	0	0