We are authorized to issue 50,000,000 shares of undesignated preferred stock, par value $0.001 per share. The undesignated preferred stock may be issued from time to time at the discretion of our board of directors. As of June 30, 2019 and 2018, no shares of undesignated preferred stock were issued or outstanding.

In February 2019, our Board of Directors authorized a program for the repurchase of up to $20.0 million in shares of common stock through open market purchases. The term of the program is 18 months. The timing and amount of repurchase transactions under this program will depend on market conditions, cash flow and other considerations. Under this program, we utilized $1.3 million of cash to repurchase 221,333 shares of our common stock at an average purchase price of $5.89 per share during fiscal 2019.

The repurchased shares are retired and designated as authorized but unissued shares. The timing and amount of repurchase transactions under our stock repurchase programs depends on market conditions and other considerations. We use the par value method of accounting for our stock repurchases. Under the par value method, common stock is first charged with the par value of the shares involved. The excess of the cost of shares acquired over the par value is allocated to additional paid-in capital, or APIC, based on an estimated average sales price per issued share with the excess amounts charged to retained earnings. As a result of our stock repurchases during fiscal 2019, we reduced common stock and APIC by an aggregate of $714,000 and charged $589,000 to retained earnings.

Under our 1999 Stock Option Plan, or 1999 Plan, 2002 Executive Stock Option Plan, or 2002 Plan, 2009 Equity Incentive Plan, or 2009 Plan, and 2011 Stock Option and Grant Plan, or 2011 Plan, eligible employees, directors, and consultants are able to participate in our future performance through awards of nonqualified stock options, incentive stock options and restricted stock units, or RSUs, through the receipt of such awards as authorized by our board of directors. Incentive stock options may be granted only to employees to purchase our common stock at prices equal to or greater than the fair market value on the date of grant. Nonqualified stock options to purchase our common stock may be granted at prices not less than 85% of the fair market value on the date of grant. Options generally vest over a four-year period beginning from the date of grant and generally expire 10 years from the date of grant. RSUs generally vest annually over a four-year period beginning from the date of grant. Prior to our initial public offering, we granted options outside of our stock option plans with terms substantially similar to the terms of options granted under our plans. Our 2009 Plan expires in October of 2019 and our 2011 Plan expires in June 2021.

On the first day of each fiscal year, the number of shares available and reserved for issuance under the 2009 Plan will be annually increased by an amount equal to the lesser of 1,666,666 shares of common stock; 4% of the outstanding shares of our common stock as of the last day of our immediately preceding fiscal year; or an amount determined by our board of directors. The last annual increase occurred in fiscal 2019, as the 2009 Plan expires in October 2019 for new awards.



	Number of shares		Weighted average exercise price per share		Weighted average remaining contractual life (years)	Aggregate intrinsic value
Options outstanding as of June 30, 2018	5,116		$	6.48
Granted	290		5.10
Exercised	(1,477	)	5.99
Canceled or expired	(520	)	6.95
Options outstanding as of June 30, 2019	3,409		$	6.49	5.53	$	5,748
As of June 30, 2019:
Options vested and expected to vest	3,341		$	6.52	5.47	$	5,564
Options exercisable	2,703		$	6.74	4.95	$	4,000

During fiscal 2019, 2018 and 2017, the total cash received from the exercise of stock options was $8.9 million, $681,000 and $2.7 million, respectively, and the total intrinsic value of stock options exercised was $1.1 million, $227,000 and $6.1 million, respectively.



	Number of Shares		Weighted average remaining contractual life (years)	Aggregate intrinsic value
RSUs outstanding as of June 30, 2018	3,068
Granted	1,195
Vested	(1,151	)
Canceled	(475	)
RSUs outstanding as of June 30, 2019	2,637		1.30	$	21,097
As of June 30, 2019:
RSUs expected to vest	2,276		1.18	$	18,205

In October 2018, the Compensation Committee of our Board of Directors approved the grant under our 2009 Equity Incentive Plan of performance-based RSUs (the “PSU Award”) covering a target of 240,000 shares of common stock to Dr. HP Jin, our Chairman of the Board of Directors, President and Chief Executive Officer, or CEO.

The PSU Award is subject to (a) four performance milestones, each requiring achievement of a specified trailing average closing stock price for a 50 trading day period on or before the three-year anniversary of the PSU Award’s grant date, as well as (b) Dr. Jin’s continued service with the Company. Achieving each individual stock price performance milestone will result in one quarter of the shares subject to the PSU Award becoming eligible to vest. If a stock price performance milestone is achieved, then one half of the shares that became eligible to vest under the PSU Award upon achievement of that stock price performance milestone will vest on the later of November 1, 2019, or the date that the Compensation Committee of our Board of Directors certifies achievement of the milestone, and the remaining one half of the shares that became eligible to vest will vest on the one-year anniversary of the date the performance milestone was achieved, in each case subject to Dr. Jin’s continued service with the Company through the applicable vesting date. The maximum number of shares subject to the PSU Award that may vest is 240,000.

Since achievement of the award is dependent on a market condition, stock-based compensation expense associated with the PSU Award is recognized regardless of whether the market condition is satisfied, provided that the requisite service period has been met. We utilized the Monte Carlo valuation method to determine the fair value and derived service periods of each of the stock price performance milestones. Total stock-based compensation expense associated with the PSU Award for fiscal 2019 was not material.

In December 2016, 70,000 RSUs granted under a 2015 Performance Share Program were canceled, as the performance conditions were not met. The cancellation of these RSUs resulted in a credit to stock-based compensation expense of $546,000, which is reflected in our results of operations for fiscal 2017.



	Number of Shares
Shares available for grant as of June 30, 2018	3,169
Additional shares authorized pursuant to annual increase provisions of 2009 Equity Incentive Plan	1,667
Granted	(1,485	)
RSUs withheld for taxes in net share settlements	367
Canceled	994
Shares available for grant as of June 30, 2019	4,712



	Fiscal Year Ended June 30,
	2019		2018		2017
Cost of revenue	$	108	$	145	$	130
Research and development	4,830		5,535		5,543
Sales and marketing	1,348		1,671		2,090
General and administrative	2,013		2,525		2,399
Total stock-based compensation expense	$	8,299	$	9,876	$	10,162

The following table summarizes total stock-based compensation expense recorded for stock options, RSUs and restricted common stock issued to employees and nonemployees (in thousands):



	Fiscal Year Ended June 30,
	2019		2018		2017
Stock option awards	$	1,644	$	2,103	$	2,384
RSU awards	6,655		7,773		7,778
Total stock-based compensation expense	$	8,299	$	9,876	$	10,162

We generally use the Black-Scholes option-pricing model to determine the fair value of stock option awards. The determination of the fair value of stock option awards on the date of grant is affected by the stock price as well as assumptions regarding a number of complex and subjective variables. These variables include expected stock price volatility over the term of the awards, actual and projected employee stock option exercise behaviors, risk-free interest rates and expected dividends. The weighted average assumptions used to value stock options granted and the resulting weighted average grant date fair value per share were as follows:



	Fiscal Year Ended June 30,
	2019			2018			2017
Expected volatility	39		%	42		%	39		%
Expected term (in years)	6.87			4.75			4.25
Risk-free interest rate	2.99		%	2.00		%	1.32		%
Dividend yield	—			—			—
Weighted average grant date fair value per share	$	2.32		$	2.14		$	1.87

We recognize the estimated stock-based compensation expense of RSUs and restricted common stock, net of estimated forfeitures, over the vesting term. The estimated stock-based compensation cost is based on the fair value of our common stock on the date of grant.

At June 30, 2019, the total unrecognized stock-based compensation expense related to employee options was $1.3 million, net of estimated forfeitures, and will be amortized over a weighted average period of 1.77 years. The total fair value of stock options that vested during fiscal 2019, 2018 and 2017 was $3.7 million, $2.4 million and $2.2 million, respectively. At June 30, 2019, the total unrecognized stock-based compensation expense related to RSUs was $8.5 million, net of estimated forfeitures, and will be amortized over a weighted average period of 2.26 years. The total fair value of RSUs that vested during fiscal 2019, 2018 and 2017 was $6.0 million, $7.0 million and $8.2 million, respectively.