Equity Incentive Plans (Tables)

12 Months Ended

Jan. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity Under Equity Incentive Plans and Related Information

A summary of activity under our equity incentive plans and related information is as follows:

	Options Outstanding
	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
								(in thousands)
Balance as of January 31, 2015		54,284,474		$	3.02		8.3	$	523,654
Options granted		19,269,524			15.76
Options exercised		(2,313,598	)		2.58
Options cancelled		(2,361,313	)		7.96
Balance as of January 31, 2016		68,879,087		$	6.43		7.9	$	505,131
Vested and exercisable as of January 31, 2016		24,297,716		$	2.04		6.7	$	267,213
Vested and expected to vest as of January 31, 2016		66,945,857		$	6.37		7.9	$	494,544

Summary of Estimate Fair Value of Employee Stock Options and Employee Purchase Plan

We estimate the fair value of employee stock options and ESPP purchase rights using a Black-Scholes option pricing model with the following assumptions:

	Fiscal Year Ended January 31,
	2014		2015		2016
Employee Stock Options
Expected term (in years)	5.3 - 7.3		5.0 - 6.9		6.0 - 7.4
Expected volatility	65% - 69%		55% - 68%		48%-52%
Risk-free interest rate	0.8% - 2.1%		1.3% - 2.2%		1.5%-1.9%
Dividend rate		—		—		—
Fair value of common stock	$1.46 - $2.98		$4.81 - $12.65		$13.94-$19.68
Employee Stock Purchase Plan
Expected term (in years)		—		—	0.4 - 1.9
Expected volatility		—		—	49%
Risk-free interest rate		—		—	0.1% - 0.7%
Dividend rate		—		—		—

Summary of Estimate Fair Value of Non-employee Stock

We estimate the fair value of non-employee stock options on the date of grant using a Black-Scholes option pricing model with the following assumptions:

	Fiscal Year Ended January 31,
	2014		2015		2016
Expected term (in years)		10.0		10.0		10.0
Expected volatility	62% - 65%		62% - 63%		49%
Risk-free interest rate	1.1% - 2.6%		1.6% - 2.6%		1.5%
Dividend rate		—		—		—
Fair value of common stock	$1.79 - $2.98		$9.40 - $12.40		$	17.00

Summarizes the Components of Stock-Based Compensation

The following table summarizes the components of stock-based compensation expense recognized in the consolidated statements of operations (in thousands):

	Fiscal Year Ended January 31,
	2014		2015		2016
Cost of revenue—product	$	253	$	303	$	276
Cost of revenue—support		316		1,273		2,388
Research and development		11,477		22,512		31,135
Sales and marketing		9,014		22,466		16,966
General and administrative		506		6,479		7,460
Total stock-based compensation	$	21,566	$	53,033	$	58,225