Note 11. Common Stock, Common Stock Warrants and Stock Option Plan.

Common Stock.

We are authorized to issue 100,000,000 shares of common stock with $0.0001 par value per share as of March 31, 2020 and December 31, 2019. Each holder of common stock is entitled to one vote per share. As of March 31, 2020, no dividends have been declared by the Board of Directors, however, the holders of common stock are also entitled to receive dividends, when and if declared by our Board of Directors.

Common Stock Reserved for Future Issuance.

As of March 31, 2020 and December 31, 2019, we had reserved shares of common stock for future issuances as follows:


	March 31,	December 31,
	2020	2019
Warrants to purchase common stock	1,165,282	1,165,282
Options outstanding	1,626,244	1,929,391
Restricted stock units outstanding	2,253,181	1,451,507
Shares available for future grants	557,671	288,813
Shares available for ESPP	547,513	373,428
Shares reserved for issuance upon conversion of the Notes	8,885,204	8,885,204
Total	15,035,095	14,093,625

Common Stock Warrants.

In connection with the Credit Agreement (Note 7), the Company issued Tennenbaum a warrant to purchase 850,000 shares of common stock at an exercise price of $8.62 per share with a term of six years.

The following common stock warrants were outstanding:


As of March 31, 2020
Total amount of securities issuable
under the outstanding warrants	Exercise Price		Issuance Date	Expiration Date
315,282	$	2.38	2014-2015	2022-2024
850,000	$	8.62	2018	2024
1,165,282	$	6.93

Common stock warrants are exercisable at the option of the holder any time after the date of issuance into shares of our common stock.

Employee Benefit Plans.

2007 Equity Incentive Plan.

In 2007, our Board of Directors and shareholders approved the 2007 Equity Incentive Plan (the “2007 Plan”) under which 272,727 shares of common stock were reserved and available for the issuance of stock options and restricted stock to eligible participants. The 2007 Plan was subsequently amended to increase the number of shares of common stock reserved for issuance under the 2007 Plan to 787,878 and during the year ended December 31, 2015, the number of shares reserved for issuance under the 2007 Plan was increased to 2,651,515. Options and restricted stock awards were granted at a price per share not less than the 85% of the fair value at the date of grant or award, respectively. Restricted stock awarded to persons controlling more than 10% of our stock were granted at a price per share not less than the 100% of the fair value at the date of the award. Options that were granted to new employees generally vest over a four-year period with 25% vesting at the end of one year and the remaining to vest monthly thereafter, while options that were granted to existing employees generally vest over a four-year period. Options granted generally are exercisable up to 10 years from the date of grant. As of October 26, 2015, no shares were available for grant under the 2007 Plan and all outstanding options would continue to be governed and remain outstanding in accordance with their existing terms. In addition, any shares subject to outstanding awards under the 2007 Plan that are issuable upon the exercise of options that expire or become unexercisable for any reason without having been exercised in full will be available for future grant and issuance under the 2015 Equity Incentive Plan.

2015 Equity Incentive Plan.

In September 2015, our Board of Directors adopted, and in October 2015 our stockholders approved, our 2015 Equity Incentive Plan. The 2015 Equity Incentive Plan became effective on the date immediately prior to the date of our initial public offering (“IPO”). As a result, 1,813,272 shares of common stock previously reserved but unissued under the 2007 Plan on the effective date of the 2015 Equity Incentive Plan became reserved for issuance under our 2015 Equity Incentive Plan, and we ceased granting awards under our 2007 Plan. The number of shares reserved for issuance under our 2015 Equity Incentive Plan will increase automatically on the first day of January of each of 2016 through 2025 by the number of shares equal to 4% of the total outstanding shares of our common stock as of the immediately preceding December 31. However, our Board of Directors may reduce the amount of the increase in any particular year.

Our 2015 Equity Incentive Plan authorizes the award of stock options, restricted stock awards, stock appreciation rights, restricted stock units (“RSUs”), performance awards and stock bonuses. No person will be eligible to receive more than 2,000,000 shares in any calendar year under our 2015 Equity Incentive Plan other than a new employee of ours, who will be eligible to receive no more than 4,000,000 shares under the plan in the calendar year in which the employee commences employment. The aggregate number of shares of our common stock that may be subject to awards granted to any one non-employee director pursuant to the 2015 Equity Incentive Plan in any calendar year shall not exceed 300,000. Our 2015 Equity Incentive Plan provides that no more than 25,000,000 shares will be issued as incentive stock options.

2015 Employee Stock Purchase Plan.

In September 2015, our Board of Directors adopted, and in October 2015 our stockholders approved, our 2015 Employee Stock Purchase Plan (“ESPP”). The 2015 Employee Stock Purchase Plan became effective on the date of our IPO. We reserved 150,000 shares of our common stock for issuance under our 2015 Employee Stock Purchase Plan. The number of shares reserved for issuance under our 2015 Employee Stock Purchase Plan will increase automatically on the first day of January following the first offering date by the number of shares equal to 1% of the total outstanding shares of our common stock as of the immediately preceding December 31 (rounded to the nearest whole share). However, our Board of Directors may reduce the amount of the increase in any particular year. The aggregate number of shares issued over the term of our 2015 Employee Stock Purchase Plan will not exceed 2,250,000 shares of our common stock.

Under our 2015 Employee Stock Purchase Plan, eligible employees will be able to acquire shares of our common stock by accumulating funds through payroll deductions. Eligible employees will be able to select a rate of payroll deduction up to 15% of their base cash compensation. The purchase price for shares of our common stock purchased under our 2015 Employee Stock Purchase Plan will be 85% of the lesser of the fair market value of our common stock on (i) the first trading day of the applicable offering period and (ii) the last trading day of each purchase period in the applicable offering period. Except for the first offering period, each offering period will run for no more than six months, with purchases occurring every six months. The first offering period began upon the effective date of our IPO and was originally set to end on June 30, 2016. On May 25, 2016, the Board of Directors extended the initial offering period to July 31, 2016. Subsequent purchase periods will be 6 months in duration beginning on August 1, 2016. On July 29, 2016, we issued 68,392 shares of common stock in conjunction with the end date of the initial purchase window. During 2017, we issued 110,711 shares of common stock pursuant to the ESPP. On January 31, 2018 we issued 55,806 shares of common stock pursuant to the ESPP. On July 31, 2018 we issued 69,761 shares of common stock pursuant to the ESPP. On January 31, 2019 we issued 129,815 shares of common stock pursuant to the ESPP. On July 31, 2019 we issued 154,116 shares of common stock pursuant to the ESPP. On January 31, 2020 we issued 128,601 shares of common stock in conjunction with the end date of the latest purchase window.

No participant will have the right to purchase shares of our common stock in an amount that has a fair market value greater than $25,000, determined as of the first day of the applicable purchase period, for each calendar year in which that right is outstanding. In addition, no participant will be permitted to purchase more than 2,500 shares during any one purchase period or a lesser amount as determined by our compensation committee.

Our 2015 Employee Stock Purchase Plan will continue until the earlier to occur of its termination by our Board of Directors, the issuance of all shares reserved for issuance under it or the tenth anniversary of its effective date.

A summary of stock option and RSUs (including performance-based RSU) activity under the 2007 Plan and the 2015 Equity Incentive Plan is as follows:


	Stock Options
				Weighted-
		Weighted-		Average
		Average		Remaining	Aggregate
		Exercise		Contractual	Intrinsic
	Shares	Price		Term (Years)	Value
	(aggregate intrinsic value in thousands)
Outstanding as of December 31, 2017	1,560,453	$	3.63	7.6	$	4,632
Granted	479,375		7.25
Exercised	(112,965)		2.48
Canceled	(61,448)		3.65
Outstanding as of December 31, 2018	1,865,415		4.63	7.6	$	1,540
Granted	189,856		6.16
Exercised	(112,647)		3.36
Canceled	(13,233)		6.53
Outstanding as of December 31, 2019	1,929,391		4.84	6.9	$	7,146
Granted	—		—
Exercised	(299,737)		3.91
Canceled	(3,410)		6.94
Outstanding as of March 31, 2020	1,626,244	$	5.01	6.9	$	10,057
Options vested and expected to vest as of March 31, 2020	1,582,822	$	4.97	6.9	$	9,849
Options vested and exercisable as of March 31, 2020	1,034,771	$	4.42	6.3	$	7,002


	Restricted Stock Units
				Weighted-
		Weighted-		Average
		Average		Remaining	Aggregate
		Grant Date		Contractual	Intrinsic
	Shares	Fair Value		Term (Years)	Value
	(aggregate intrinsic value in thousands)
Outstanding as of December 31, 2017	509,894	$	2.84	1.4	$	3,288
Granted	925,578		6.55
Released	(264,568)		4.02
Forfeited/expired	(15,924)		8.34
Outstanding as of December 31, 2018	1,154,980		5.50	1.4	$	5,082
Granted	978,851		6.35
Released	(512,703)		5.31
Forfeited/expired	(169,621)		5.15
Outstanding as of December 31, 2019	1,451,507		6.18	1.3	$	12,314
Granted	958,825		7.88
Released	(143,625)		5.40
Forfeited/expired	(13,526)		7.67
Outstanding as of March 31, 2020	2,253,181	$	6.94	1.5	$	25,182