Net Loss per Share - Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Numerator:
Net loss attributable to Coupa Software Incorporated, Basic	$ (379,039)	$ (180,117)	$ (90,832)
Net loss attributable to Coupa Software Incorporated, Diluted	$ (379,039)	$ (180,117)	$ (90,832)
Denominator:
Weighted-average number of shares used in computing net loss per share, Basic (in shares)	73,816	68,559	62,484
Weighted-average number of shares used in computing net loss per share, Diluted (in shares)	73,816	68,559	62,484
Net loss per share, attributable to Coupa Software Incorporated, Basic (in dollars per share)	$ (5.13)	$ (2.63)	$ (1.45)
Net loss per share, attributable to Coupa Software Incorporated, Diluted (in dollars per share)	$ (5.13)	$ (2.63)	$ (1.45)