Net Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net loss attributable to Marketo	$ (17,151)	$ (18,238)	$ (17,950)	$ (18,158)	$ (15,913)	$ (12,803)	$ (13,112)	$ (12,509)	$ (71,497)	$ (54,337)	$ (47,360)
Denominator:
Weighted-average common shares outstanding									42,616	40,602	24,881
Less: Weighted-average unvested common shares subject to repurchase or forfeiture and shares held in escrow									(112)	(217)	(172)
Weighted-average shares used in computing net loss per share of common stock, basic and diluted									42,504	40,385	24,709
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (0.40)	$ (0.43)	$ (0.43)	$ (0.44)	$ (0.39)	$ (0.31)	$ (0.33)	$ (0.32)	$ (1.68)	$ (1.35)	$ (1.92)
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation									7,168	8,098	7,493
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									3,777	5,404	6,343
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	159	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									12	50	127
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									127	125	304
RSUs
Potentially dilutive securities that were excluded from the diluted per share
Potentially dilutive securities excluded from the diluted per share calculation									3,230	2,360	582