9. Stock-Based Compensation

The total stock-based compensation the Company recognized for stock-based awards in the condensed consolidated statements of operations is as follows (in thousands):

	Three Months Ended July 31,				Six Months Ended July 31,
	2016		2015		2016		2015
Total cost of revenue	$	243	$	65	$	478	$	123
Sales and marketing		355		73		681		129
Research and development		863		239		1,807		456
General and administrative		938		361		1,907		581
Total stock-based compensation expense	$	2,399	$	738	$	4,873	$	1,289

The following table presents stock-based compensation expense by award-type (in thousands):

	Three Months Ended July 31,				Six Months Ended July 31,
	2016		2015		2016		2015
Stock options	$	630	$	691	$	1,314	$	1,242
Restricted stock units		1,512		29		3,020		29
Employee stock purchase plan		257		18		539		18
Total stock-based compensation expense	$	2,399	$	738	$	4,873	$	1,289

As of July 31, 2016, there was $4.4 million, $13.6 million and $1.3 million of unrecognized share-based compensation expense, net of estimated forfeitures, related to non-vested stock option grants, unvested RSUs and ESPP, respectively, which will be recognized on a straight-line basis over the remaining weighted-average vesting periods of approximately 2.1 years, 2.9 years and 0.9 years, respectively.

Total outstanding non-employee stock options were 50,720 and 87,199 at July 31, 2016 and 2015, respectively. The total outstanding non-employee RSUs were 85,250 at July 31, 2016. There were no outstanding non-employee RSUs at July 31, 2015. The non-employee stock-based compensation expense for the stock options and RSUs was not material for any of the periods presented.

Prior to the Company’s IPO, the fair value of the shares of common stock underlying stock options was historically established by the Company’s Board of Directors, and was based in part upon a valuation provided by an independent third-party valuation firm. Subsequent to the completion of the IPO, the Company uses the closing price of common stock as reported on the New York Stock Exchange on the grant date. The Company has consistently used peer company volatilities for calculating the expected volatilities for employee stock options and the ESPP. The expected term of options granted to employees is based on the simplified method as the Company does not have sufficient historical exercise data, and the expected term of the ESPP is based on the contractual term. The risk-free interest rate for the expected term of the options and the ESPP is based on the U.S. Treasury yield curve in effect at the time of grant. The Company recognizes its stock-based compensation related to options and RSUs using a straight-line method over the vesting term. The Company recognizes its stock-based compensation related to ESPP using a straight-line method over the offering period.

The Company did not grant any stock options during the six months ended July 31, 2016. For the three and six months ended July 31, 2015 the fair value of employee stock options grants was estimated using the Black–Scholes model with the following assumptions:

	Three Months Ended July 31,	Six Months Ended July 31,
	2015	2015
Stock Options:
Expected volatility	54%-59%	54%-62%
Expected term (in years)	5.3-6.1	5.3-6.1
Risk-free interest rate	1.7%-1.9%	1.6%-1.9%
Dividend yield	— %	— %

For the three and six months ended July 31, 2016 and 2015 the fair value of the Company’s employee stock purchase plan was estimated using the Black – Scholes model with the following assumptions:

	Three Months Ended July 31,		Six Months Ended July 31,
	2016	2015	2016	2015
ESPP:
Expected volatility	44%-50%	35%-43%	44%-50%	35%-43%
Expected term (in years)	0.5-2.0	0.7-2.2	0.5-2.0	0.7-2.2
Risk-free interest rate	0.5%-1.0%	0.1%-0.7%	0.5%-1.0%	0.1%-0.7%
Dividend yield	— %	— %	— %	— %

Early Exercise of Common Stock

During the three and six months ended July 31, 2016, the Company issued 29,485 shares and 97,989 shares of common stock following the exercise of common stock options prior to their vesting dates, or early exercises. During the three and six months ended July 31, 2016, 1,771 common stock options were early exercised prior to their vesting. The amounts received from all such early exercises is recorded in accrued expenses and other long-term liabilities on the consolidated balance sheets and reclassified to stockholders’ equity as the options vest. The unvested shares are subject to the Company’s repurchase right at the original purchase price, which lapses over the vesting term of the original option grant. As of July 31, 2016 and January 31, 2016, the aggregate proceeds from exercises of common stock options subject to repurchase recorded in accrued expenses and other long-term liabilities totaled $0.1 million and $0.2 million, respectively.