	As of January 31,
	2019		2018
Restricted stock units outstanding		1,925,311		1,966,895
Options to purchase common stock		1,691,272		1,801,232
Shares available for future issuance under stock plans		1,141,482		928,024
Shares reserved under ESPP		249,933		598,033
Warrants to purchase common stock		1,107		4,881
Total shares reserved for issuance		5,009,105		5,299,065

The Company’s 2015 Plan provides for the grant of incentive stock options to its employees and any of its subsidiary corporations’ employees, and for the grant of RSUs, non-statutory stock options, stock appreciation rights, restricted stock, performance units and performance shares to its employees, directors and consultants and its subsidiary corporations’ employees and consultants.

Stock Options. Options to purchase shares of common stock may be granted to employees, directors and consultants. These options vest from date of grant to up to five years and expire ten years from the date of grant. Options may be exercised anytime during their term in accordance with the vesting/exercise schedule specified in the recipient’s stock option agreement and in accordance with the plan provisions. Shares issued upon exercise prior to vesting, are subject to a right of repurchase, which lapses according to the original option vesting schedule.

				Weighted Average		Weighted Average		Aggregate
	Number of			Exercise Price		Contractual Term		Intrinsic Value
	Shares			Per Share		(in years)		(in thousands)
Balance as of January 31, 2018		1,801,232		$	6.09		6.2	$	8,270
Granted		100,000		$	11.75
Exercised		(185,535	)		6.03
Canceled		(24,425	)		9.48
Balance as of January 31, 2019		1,691,272		$	6.39		5.4	$	14,755
Vested and exercisable - January 31, 2019		1,525,946		$	5.86		5.1	$	14,112

The aggregate intrinsic value of vested options exercised during fiscal 2019, 2018 and 2017 was $1.3 million, $0.3 million and $1.3 million, respectively. The weighted average grant date fair value of options granted during fiscal 2019, 2018 and 2017 was $5.28 per share, $4.81 per share and zero , respectively. No stock options were granted during fiscal 2017.

Restricted Stock Units. RSUs may be granted to employees, non-employee board members and consultants. These RSUs vest ratably over a period ranging from one to four years, and are subject to the participant’s continuing service to the Company over that period. Until vested, RSUs do not have the voting and dividend participation rights of common stock and the shares underlying the awards are not considered issued and outstanding.

	Number of Shares			Weighted Average Grant-Date Fair Value Per Share
Balance as of January 31, 2017		1,859,196		$	7.65
Granted		1,222,605			10.17
Vested		(936,869	)		8.54
Canceled		(178,037	)		8.77
Balance as of January 31, 2018		1,966,895			8.85
Granted		1,176,647			11.96
Vested		(921,533	)		9.12
Canceled		(296,698	)		9.70
Balance as of January 31, 2019		1,925,311		$	10.49

Vested RSUs included shares of common stock that the Company withheld on behalf of certain employees to satisfy the minimum statutory tax withholding requirements, as defined by the Company. The Company withheld an aggregate amount of $2.9 million, $2.4 million and $1.6 million in fiscal 2019, 2018 and 2017, respectively, which were classified as financing cash outflows in the consolidated statements of cash flows. The Company canceled and returned these shares to the 2015 Plan, which are available under the plan terms for future issuance.

The ESPP allows eligible employees to purchase shares of common stock at a discount through payroll deductions of up to 15% of their eligible compensation (subject to plan limitations). The ESPP provides for a 24-month offering period comprised of four purchase periods of approximately six months. Employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock as of the first date or the ending date of each six-month offering period. The offering periods are scheduled to start on the first trading day on or after March 15 and September 15 of each year.

During fiscal 2019, 2018 and 2017, employees purchased 0.3 million, 0.3 million and 0.2 million shares, respectively, at a weighted purchase price of $6.82, $5.48 and $5.01 per share, respectively.