Net Loss per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator:
Net loss attributable to Marketo	$ (18,238)	$ (12,803)	$ (54,346)	$ (38,424)
Denominator:
Weighted-average common shares outstanding	42,876	40,872	42,345	40,383
Less: Weighted-average unvested common shares subject to repurchase or forfeiture and shares held in escrow	(41)	(204)	(137)	(226)
Weighted-average shares used in computing net loss per share of common stock, basic and diluted	42,835	40,668	42,208	40,157
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.43)	$ (0.31)	$ (1.29)	$ (0.96)
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			7,460	7,708
Stock options to purchase common stock
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			4,093	5,529
Employee Stock Purchase Plan
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			132	132
Common stock held in escrow
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			22	137
Common stock subject to repurchase
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			17	62
RSUs
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			3,196	1,848