Equity Incentive Plans - Summary of Activity Under the Equity Incentive Plans (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Oct. 31, 2015 USD ($) $ / shares shares	Jan. 31, 2015 USD ($) $ / shares shares
Options Outstanding, Number of Shares
Options Outstanding, Number of Shares, Beginning Balance | shares	54,284,474
Options Outstanding, Number of Shares, Options granted | shares	18,159,824
Options Outstanding, Number of Shares, Options exercised | shares	(1,784,066)
Options Outstanding, Number of Shares, Options cancelled | shares	(1,730,681)
Options Outstanding, Number of Shares, Ending Balance | shares	68,929,551	54,284,474
Options Outstanding, Number of Shares, Vested and exercisable | shares	21,903,812
Options Outstanding, Number of Shares, Vested and expected to vest | shares	66,851,238
Options Outstanding, Weighted Average Exercise Price
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 3.02
Weighted Average Exercise Price, Options granted | $ / shares	15.77
Weighted Average Exercise Price, Options exercised | $ / shares	2.64
Weighted Average Exercise Price, Options Cancelled | $ / shares	7.09
Weighted Average Exercise Price, Ending Balance | $ / shares	6.29	$ 3.02
Weighted Average Exercise Price, Vested and exercisable | $ / shares	1.71
Weighted Average Exercise Price, Vested and expected to vest | $ / shares	$ 6.22
Options Outstanding, Weighted Average Remaining Contractual Life (In Years)
Weighted Average Remaining Contractual Life (In Years)	0 years	8 years 3 months 18 days
Weighted Average Remaining Contractual Life (In Years), Vested and exercisable	6 years 9 months 18 days
Weighted Average Remaining Contractual Life (In Years), Vested and expected to vest	8 years 1 month 6 days
Options Outstanding, Aggregate Intrinsic Value
Aggregate Intrinsic Value, Beginning Balance | $	$ 523,654
Aggregate Intrinsic Value, Ending Balance | $	0	$ 523,654
Aggregate Intrinsic Value, Vested and exercisable | $	348,767
Aggregate Intrinsic Value, Vested and expected to vest | $	$ 763,519