Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 4,739,472	$ 1,477,143	$ 354,254
Grants receivable	239,539us-gaap_GrantsReceivableCurrent	84,344us-gaap_GrantsReceivableCurrent
Prepaid expenses - clinical operations			0mbvx_PrepaidClinicalExpensesCurrent
Prepaid expenses	302,155us-gaap_PrepaidExpenseCurrent	334,629us-gaap_PrepaidExpenseCurrent	44,408us-gaap_PrepaidExpenseCurrent
Other current assets	400us-gaap_OtherAssetsCurrent	14,675us-gaap_OtherAssetsCurrent
Total current assets	5,281,566us-gaap_AssetsCurrent	1,910,791us-gaap_AssetsCurrent	398,662us-gaap_AssetsCurrent
Property and equipment, net	81,597us-gaap_PropertyPlantAndEquipmentNet	57,053us-gaap_PropertyPlantAndEquipmentNet	24,487us-gaap_PropertyPlantAndEquipmentNet
Goodwill	6,826,003us-gaap_Goodwill	6,826,003us-gaap_Goodwill
Other long term assets	11,017us-gaap_OtherAssetsNoncurrent	11,017us-gaap_OtherAssetsNoncurrent	14,285us-gaap_OtherAssetsNoncurrent
Total assets	12,200,183us-gaap_Assets	8,804,864us-gaap_Assets	437,434us-gaap_Assets
Current liabilities:
Accounts payable	2,066,431us-gaap_AccountsPayableCurrent	1,313,247us-gaap_AccountsPayableCurrent	66,977us-gaap_AccountsPayableCurrent
Accrued compensation	318,815	230,381	169,123
Accrued clinical operations and site costs	516,957us-gaap_AccruedLiabilitiesCurrent	494,110us-gaap_AccruedLiabilitiesCurrent	773,523us-gaap_AccruedLiabilitiesCurrent
Related party liabilities			240,000us-gaap_DueToRelatedPartiesCurrent
Accrued lease contingency fee	590,504	590,504
Other accrued expenses	445,904us-gaap_OtherAccruedLiabilitiesCurrent	245,421us-gaap_OtherAccruedLiabilitiesCurrent	24,963us-gaap_OtherAccruedLiabilitiesCurrent
Warrant liability		92,463mbvx_FairValueOfWarrantLiability
Total current liabilities	3,938,611us-gaap_LiabilitiesCurrent	2,966,126us-gaap_LiabilitiesCurrent	1,274,586us-gaap_LiabilitiesCurrent
Redeemable convertible preferred stock:
Redeemable convertible preferred stock, value		1,838,025	12,525,182
Stockholders' equity:
Common stock	125,255us-gaap_CommonStockValue	28,029us-gaap_CommonStockValue	2,305us-gaap_CommonStockValue
Additional paid-in capital	53,077,718	24,492,450	607,913
Accumulated deficit	(44,943,783)	(24,550,308)	(13,972,552)
Total stockholders' equity	8,261,572us-gaap_StockholdersEquity	4,000,713us-gaap_StockholdersEquity	(13,362,334)us-gaap_StockholdersEquity
Total liabilities, redeemable convertible preferred stock and stockholders' equity	12,200,183	8,804,864	437,434
Redeemable Mabvax Series A [Member]
Redeemable convertible preferred stock:
Redeemable convertible preferred stock, value			5,787,906
Redeemable Mabvax Series B [Member]
Redeemable convertible preferred stock:
Redeemable convertible preferred stock, value			6,737,276
Redeemable Mabvax Ther. Series B [Member]
Redeemable convertible preferred stock:
Redeemable convertible preferred stock, value		1,838,025
Series A-1 Convertible Preferred Stock [Member]
Stockholders' equity:
Convertible preferred stock		4,029,576
Series C Convertible Preferred Stock [Member]
Stockholders' equity:
Convertible preferred stock		966
Series D Convertible Preferred Stock [Member]
Stockholders' equity:
Convertible preferred stock	$ 2,382

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-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 4.E)

-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section E

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29-31)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30, 31

-Article 5

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