DOCUMENT AND ENTITY INFORMATION - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Feb. 29, 2020	Jul. 31, 2019
DOCUMENT AND ENTITY INFORMATION
Document Type	10-K
Document Period End Date	Jan. 31, 2020
Entity Registrant Name	BioPharmX Corp
Is Entity a Well-known Seasoned Issuer	No
Is Entity a Voluntary Filer	No
Is Entity's Reporting Status Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 5.9
Entity Common Stock, Shares Outstanding		18,278,219
Entity Central Index Key	0001504167
Amendment Flag	false
Current Fiscal Year End Date	--01-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020