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

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Cost of revenues	$	15	$	19	$	31	$	29
Sales and marketing		236		404		666		608
General and administrative		261		479		868		697
Research and development		134		120		277		189
Total	$	646	$	1,022	$	1,842	$	1,523

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 vest ratably in three equal installments on the first, second and third anniversaries of the grant date. As of June 30, 2020, there were 1.3 million shares available for future issuance under the 2018 Plan.

The following table summarizes the Company’s stock option activity for the six months ended June 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		28		$	2.94
Exercised		(98	)	$	1.28
Forfeited		(480	)	$	11.16
Outstanding at June 30, 2020		1,865		$	6.31		5.2	$	527
Exercisable at June 30, 2020		1,312		$	4.63		3.8	$	527
Vested and expected to vest at June 30, 2020		1,865		$	6.31		5.2	$	527

The Company recognized share-based compensation expense related to stock options of $0.3 million and $0.7 million for the three months ended June 30, 2020 and 2019, respectively and $0.8 million and $1.0 million for the six months ended June 30, 2020 and June 30, 2019. As of June 30, 2020, there was $2.8 million of total unrecognized compensation cost related to non-vested stock options which the Company expects to recognize over a weighted-average period of 2.6 years. The weighted-average grant-date fair value of stock options granted during the six months ended June 30, 2020 was estimated at $1.52 per option. The total intrinsic value of stock options exercised during the six months ended June 30, 2020 was $0.2 million.

For the six months ended June 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	$	2.94
Exercise price	$	2.94
Expected term (in years)		6.1
Risk-free interest rate		1	%
Expected volatility		55	%
Dividend yield		0	%

The following table summarizes the Company’s restricted stock award and restricted stock unit activity for the six months ended June 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		1,504		$	3.40
Vested		(66	)	$	15.26
Forfeited		(394	)	$	5.34
Non-vested at June 30, 2020		1,289		$	4.45

The Company recognized $0.4 million and $0.3 million in share-based compensation expense related to restricted stock awards and restricted stock units for the three months ended June 30, 2020 and 2019, respectively and $1.0 million and $0.5 million for the six months ended June 30, 2020 and 2019. As of June 30, 2020, there was $4.8 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 2.3 years. The total fair value at the vesting date of restricted stock awards and restricted stock units vested during the six months ended June 30, 2020 was $0.2 million.