The amount of share-based compensation expense recognized by the Company by location in its statements of operations for the three and nine months ended September 30, 2020 and 2019 is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Cost of revenues	$	17	$	18	$	48	$	47
Sales and marketing		370		368		1,036		976
General and administrative		572		429		1,440		1,126
Research and development		87		119		364		309
Total	$	1,046	$	934	$	2,888	$	2,458

In June 2018, the Company adopted the 2018 Equity Incentive Plan, or 2018 Plan, which authorized the issuance of up to 1.4 million shares, subject to an annual 4% increase based on the number of shares of common stock outstanding, in the form of restricted stock, stock appreciation rights and stock options to the Company’s directors, employees and consultants. The amount and terms of grants are determined by the Company’s board of directors. All stock options granted to date have had exercise prices equal to the fair value, as determined by the closing price as reported by the Nasdaq Global Market, of the underlying common stock on the date of grant. The contractual term of stock options is up to 10 years, and stock options are exercisable in cash or as otherwise determined by the board of directors. Generally, stock options vest 25% upon the first anniversary of the date of grant and the remainder ratably monthly thereafter for 36 months. Restricted stock awards and restricted stock units generally vest ratably in three equal installments on the first, second and third anniversaries of the grant date. As of September 30, 2020, there were 1.4 million shares available for future issuance under the 2018 Plan.

The following table summarizes the Company’s stock option activity for the nine months ended September 30, 2020:

	Number of Shares under Option (in thousands)			Weighted- average Exercise Price per Option		Weighted- average Remaining Contractual Life (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2019		2,415		$	7.11
Granted		1,029		$	2.01
Exercised		(230	)	$	2.32
Forfeited		(620	)	$	10.74
Outstanding at September 30, 2020		2,594		$	4.64		7.0	$	5,535
Exercisable at September 30, 2020		1,850		$	4.79		4.1	$	2,495
Vested and expected to vest at September 30, 2020		2,594		$	4.64		7.0	$	5,535

The Company recognized share-based compensation expense related to stock options of $0.3 million and $0.6 million for the three months ended September 30, 2020 and 2019, respectively and $1.2 million and $1.6 million for the nine months ended September 30, 2020 and 2019. As of September 30, 2020, there was $3.3 million of total unrecognized compensation cost related to non-vested stock options which the Company expects to recognize over a weighted-average period of 2.8 years. The weighted-average grant-date fair value of stock options granted during the nine months ended September 30, 2020 was estimated at $1.02 per option. The total intrinsic value of stock options exercised during the nine months ended September 30, 2020 was $0.4 million.

For the nine months ended September 30, 2020, the grant-date fair value of stock options was estimated at the time of grant using the following weighted-average inputs and assumptions in the Black-Scholes option pricing model:

Estimated fair value of common stock	$	2.01
Exercise price	$	2.01
Expected term (in years)		6.1
Risk-free interest rate		0.38	%
Expected volatility		55.3	%
Dividend yield		0	%

The following table summarizes the Company’s restricted stock award and restricted stock unit activity for the nine months ended September 30, 2020:

	Non-vested Restricted Stock Units (in thousands)			Weighted- average Grant-date Fair Value
Non-vested at December 31, 2019		245		$	15.23
Granted		2,155		$	3.05
Vested		(87	)	$	14.13
Forfeited		(463	)	$	5.22
Non-vested at September 30, 2020		1,850		$	3.60

The Company recognized $0.6 million and $0.3 million in share-based compensation expense related to restricted stock awards and restricted stock units for the three months ended September 30, 2020 and 2019, respectively and $1.7 million and $0.9 million for the nine months ended September 30, 2020 and 2019. As of September 30, 2020, there was $6.1 million of unrecognized compensation cost related to non-vested restricted stock awards and restricted stock units, which the Company expects to recognize over a weighted-average period of 2.6 years. The total fair value at the vesting date of restricted stock awards and restricted stock units vested during the nine months ended September 30, 2020 was $0.2 million.

In July 2020, the Company awarded 500,000 of performance restricted stock units (“PRSUs”) to the Company’s chief executive officer in connection with the commencement of his employment. The grant was comprised of four equal tranches each of which vest in equal installments of 125,000 shares based on appreciation of the Company’s common stock price to $10, $15, $20 and $25 per share, respectively, measured using a trailing 30-day volume weighted average price of a share of the Company’s common stock. The fair value of the PRSUs was determined based upon a risk neutral Monte Carlo simulation valuation model. The Company’s assumptions for expected volatility, closing price and risk-free rate were 87.4%, $1.98 and 0.63%, respectively. The aggregate estimated fair value of the PRSUs was $0.9 million, which is expected to be recognized over a weighted-average period of 3.9 years. The Company recognized less than $0.1 million in share-based expense related to the PRSU award for the three and nine months ended September 30, 2020. As of September 30, 2020, there was $0.8 million of unrecognized compensation costs which the Company plans to recognize over the initial estimated vesting period of 3.7 years.