Net Loss per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net loss attributable to Marketo	$ (17,950)	$ (13,112)	$ (36,108)	$ (25,621)
Denominator:
Weighted-average common shares outstanding	42,333	40,494	42,075	40,134
Less: Weighted-average unvested common shares subject to repurchase or forfeiture and shares held in escrow	(170)	(223)	(186)	(236)
Weighted-average shares used in computing net loss per share of common stock, basic and diluted	42,163	40,271	41,889	39,898
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.43)	$ (0.33)	$ (0.86)	$ (0.64)
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			7,828	7,823
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			4,498	5,974
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			110	123
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			23	76
RSUs
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation			3,175	1,513