Stock-based compensation expense for the years ended December 31, 2020 and 2019 was classified in the consolidated statements of operations as follows:

	Year Ended December 31,
	2020		2019
	(000's)
Research and development	$	605	$	383
General and administrative		3,411		532
Total	$	4,016	$	915

Prior to the Merger, Compass Therapeutics LLC maintained an incentive pool of unit-based awards that were granted to board members, employees and consultants and accounted for as unit-based compensation. Upon consummation of the Merger, all outstanding vested profits interests units were converted into shares of the Company’s common stock. Unvested units were converted into restricted shares of the Company’s common stock and will continue to vest under the same terms as the original profits interests.

A summary of the Company’s restricted share activity during the year ended December 31, 2020 is as follows:

Weighted Average Grant Date Fair Value	Shares (000's)			Estimated Fair Value Per Share
Unvested, January 1, 2020		2,039		$	2.04
Granted		1		$	2.34
Vested		(474	)	$	1.66
Forfeited or canceled		(670	)	$	1.75
Unvested, December 31, 2020		896		$	2.46

The weighted-average grant-date fair value for unvested restricted stock as of December 31, 2020 was $2.46 per share. No restricted share awards have been granted following the Merger. As of December 31, 2020, remaining unrecognized compensation cost related to unvested restricted stock awards to be recognized in future periods totaled $1.6 million, which is expected to be recognized over a weighted average period of 1.8 years.

The fair value of each restricted stock award was estimated on the date of grant using the weighted average assumptions in the table below:

	Year Ended December 31,
	2020			2019
Expected term (in years)		6.0			6.0
Risk-free rate		0.36	%	1.61% - 2.43%
Expected volatility		140	%	65% - 85%

In June 2020, the Company’s board of directors adopted the 2020 Plan and reserved 2.9 million shares of common stock for issuance under this plan. The 2020 Plan provides that the number of shares reserved and available for issuance under the 2020 Plan will automatically increase each January 1, beginning on January 1, 2021, by the lesser of (i) 4% of the outstanding number of shares of our common stock on the immediately preceding December 31 or (ii) such number of shares as determined by the plan administrator no later than the immediately preceding December 31. As of December 31, 2020, 772 thousand shares remain available for future grant.

The 2020 Plan authorizes the board of directors or a committee of the board to grant incentive stock options, nonqualified stock options and restricted stock awards to eligible officers, employees, consultants and directors of the Company. Options generally vest over a period of four years and have a contractual life of ten years from the date of grant.

	Number of Nonvested Options (000's)			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Life (in years)
Outstanding at January 1, 2020		—		$	—
Granted		2,175		$	5.00
Exercise		-		$	—
Forfeited/cancelled		(16	)	$	5.00
Outstanding at December 31, 2020		2,159		$	5.00		9.69
Vested at December 31, 2020		890		$	5.00		9.65

For the year ended December 31, 2020, the weighted average grant date fair value for options granted was $3.44. The aggregate intrinsic value for options vested and outstanding as of and for the year ended December 31, 2020 was de minimis. As of December 31, 2020, the unrecognized compensation cost related to outstanding options was $4.3 million, expected to be recognized over a weighted average period of approximately 2.5 years.

The weighted average assumptions used in the Black-Scholes option pricing model to determine the fair value of stock options granted to employees and directors during the year ended December 31, 2020 were as follows: