Net Loss per Share - Schedule of Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Apr. 30, 2018
Apr. 30, 2017
Earnings Per Share [Abstract]    
Net loss $ (29,164) $ (19,690)
Weighted-average shares used to compute net loss per share, basic and diluted (in shares) 50,350,052 13,164,559
Net loss per share, basic and diluted (in dollars per share) $ (0.58) $ (1.50)