Condensed Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Revenues:
Grants	$ 239,539us-gaap_RevenueFromGrants	$ 94,900us-gaap_RevenueFromGrants
Total revenues	239,539us-gaap_Revenues	94,900us-gaap_Revenues
Operating costs and expenses:
Research and development	1,725,893us-gaap_ResearchAndDevelopmentExpense	394,238us-gaap_ResearchAndDevelopmentExpense
General and administrative	980,589us-gaap_GeneralAndAdministrativeExpense	673,321us-gaap_GeneralAndAdministrativeExpense
Total operating costs and expenses	2,706,482us-gaap_OperatingExpenses	1,067,559us-gaap_OperatingExpenses
Loss from operations	(2,466,943)us-gaap_OperatingIncomeLoss	(972,659)us-gaap_OperatingIncomeLoss
Interest and other income (expense)	(184)us-gaap_OtherNonoperatingIncomeExpense	(239)us-gaap_OtherNonoperatingIncomeExpense
Change in fair value of warrant liability	19,807mbvx_ChangeInFairValueOfWarrant
Net loss	(2,447,320)us-gaap_NetIncomeLoss	(972,898)us-gaap_NetIncomeLoss
Deemed dividend on Series A-1 preferred stock	(9,017,512)	(2,214,910)
Deemed dividend on Series A-1 warrant	(179,411)mbvx_DeemedDividendOnSeriesA1Warrant
Deemed dividend on Series B preferred stock	(8,655,998)
Accretion of preferred stock dividends	(93,234)	(31,934)
Net loss allocable to common stockholders	$ (20,393,475)	$ (3,219,742)
Basic and diluted net loss per share	$ (6.25)	$ (12.67)
Shares used to calculate basic and diluted net loss per share	3,262,599	254,218

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