Stockholders’ Equity (Deficit)

Authorized Stock

We are authorized to issue 1,020,000,000 shares, consisting of 1,000,000,000 shares of common stock, par value $0.001 per share, and 20,000,000 shares of preferred stock, par value $0.001 per share. Our board of directors is authorized, without stockholder approval, except as required by the listing standards of the New York Stock Exchange, to issue additional shares of our capital stock.

Common Stock

Dividend Rights—Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of our common stock are entitled to receive dividends out of funds legally available if our board of directors, in its discretion, determines to issue dividends and then only at the times and in the amounts that our board of directors may determine.

Voting Rights—Holders of our common stock are entitled to one vote for each share held on all matters submitted to a vote of stockholders.

Preemptive or Similar Rights—Our common stock is not entitled to preemptive rights, and is not subject to conversion, redemption or sinking fund provisions.

Liquidation Distributions—If we become subject to a liquidation, dissolution or winding-up, the assets legally available for distribution to our stockholders would be distributable ratably among the holders of our common stock and any participating preferred stock outstanding at that time, subject to prior satisfaction of all outstanding debt and liabilities and the preferential rights of and the payment of liquidation preferences, if any, on any outstanding shares of preferred stock.

Preferred Stock

Our board of directors is authorized to issue preferred stock in one or more series, to establish the number of shares to be included in each series, and to fix the designation, powers, preferences and rights of the shares of each series and any of its qualifications, limitations or restrictions. Our board of directors may also authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of our common stock.

Employee Stock Purchase Plan

Our ESPP allows eligible employee participants to purchase shares of our common stock at a discount through payroll deductions. The ESPP consists of offering periods that are approximately six months in length and employees may purchase shares in each period at 85% of the lower of our fair market value on the first trading day of each offering period or on the purchase date. The ESPP will continue until the earlier to occur of (i) the termination of the ESPP by our board of directors, or (ii) June 15, 2035. As of February 28, 2017, we had reserved 673,745 shares of our common stock for issuance under the ESPP and all such shares remain available for future issuance.

The following weighted-average input assumptions were used to estimate the fair value of ESPP grants:



	Year Ended February 28/29,
	2017			2016			2015
Expected volatility	40		%	42		%	—		%
Expected term (in years)	0.50			0.50			0.00
Risk-free interest rate	0.41		%	0.27		%	—		%
Dividend yield	—			—			—
Estimated fair value of stock options granted during the year	$	5.25		$	5.37		$	—

Stock Option Plan and Restricted Stock Units

Our stock plans provide for the grant of stock options, stock appreciation rights, restricted stock and restricted stock units ("RSUs") to employees, directors and contractors. Options granted are exercisable for periods not to exceed 10 years. Options and RSUs granted typically vest over three or four years, contingent upon employment or service with us on the vesting date. The following table presents shares authorized and available for grant:



	Shares Available for Grant
Balance at February 29, 2016	6,360,677
Authorized	2,346,083
Granted	(2,232,166	)
Canceled/forfeited	1,113,224
Balance at February 28, 2017	7,587,818

The following weighted-average input assumptions were used to estimate the fair value of employee stock option grants:



	Year Ended February 28/29,
	2017			2016			2015
Expected volatility	44		%	43		%	45		%
Expected term (in years)	6.21			6.25			6.25
Risk-free interest rate	1.52		%	1.80		%	1.87		%
Dividend yield	—			—			—
Estimated fair value of stock options granted during the year	$	7.95		$	13.80		$	13.98

The following table summarizes stock option activity under our plans:



	Options Outstanding
	Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value
					(in years)
Balance at February 29, 2016	4,208,201		$	20.42
Granted	279,746		$	20.04
Exercised	(622,848	)	$	12.52
Canceled/forfeited	(350,821	)	$	27.86
Balance at February 28, 2017	3,514,278		$	21.05
As of February 28, 2017:
Vested and exercisable	2,580,061		$	18.60	6.00	$	19,423,229
Vested and expected to vest	3,435,251		$	20.78	6.49	$	21,317,808

During fiscal 2017, 2016 and 2015, the total grant-date fair value of stock options vested was $7.9 million, $10.5 million and $7.5 million, respectively. During fiscal 2017, 2016 and 2015, the aggregate intrinsic value of stock option awards exercised, which is measured as the difference between the exercise price and the value of our common stock at the date of exercise, was $5.1 million, $8.6 million and $33.1 million, respectively.

As of February 28, 2017, there was $9.2 million of unrecognized compensation cost related to outstanding stock options, net of forecasted forfeitures, expected to be recognized over a weighted-average period of 1.92 years. To the extent the actual forfeiture rate is different from what we have estimated, stock-based compensation related to these options will be different from our expectations.

The following table summarizes RSU activity under our plan:



	Unvested Restricted Stock Units
	Number of Shares		Weighted- Average Grant Date Fair Value
Unvested at February 29, 2016	2,450,819		$	25.38
Granted	1,952,420		$	19.46
Vested	(882,851	)	$	23.18
Canceled/forfeited	(427,911	)	$	22.83
Unvested at February 28, 2017	3,092,477		$	22.62
Expected to vest after February 28, 2017	2,719,152		$	22.71

As of February 28, 2017, there was $49.0 million of unrecognized compensation cost related to unvested RSUs, net of forecasted forfeitures. This amount is expected to be recognized over a weighted-average period of 2.71 years. To the extent the actual forfeiture rate is different from what we have estimated, stock-based compensation related to these RSUs will be different from our expectations.

Total stock-based compensation expense has been classified as follows in the consolidated statements of operations (in thousands):



	Year Ended February 28//29,
	2017		2016		2015
Cost of revenue	$	1,367	$	1,062	$	389
Research and development	11,651		8,247		4,410
Sales and marketing	8,074		6,566		3,811
General and administrative	11,613		12,971		8,448
	$	32,705	$	28,846	$	17,058

Stock Repurchase Program

In September 2015, our board of directors authorized a stock repurchase program to repurchase shares of our common stock for an aggregate purchase price not to exceed $50.0 million through September 30, 2017. The stock repurchase program does not obligate us to repurchase any specific dollar amount or to acquire any specific number of shares. Stock will be purchased from time to time, in the open market or through private transactions, subject to market condition, in compliance with applicable state and federal securities laws. The timing and amount of repurchases, if any, will depend upon several factors, including market and business conditions, the trading price of our common stock and the nature of other investment opportunities.

The following table summarizes our common stock repurchases (in thousands, except per share data):



	Year Ended February 28//29,
	2017		2016		2015
Total number of shares repurchased	498		1,503		—
Dollar amount of shares repurchased	$	7,596	$	19,216	$	—
Average price paid per share	$	15.25	$	12.79	$	—
Remaining amount authorized as of the end of period	$	23,188	$	30,784	$	—