Stock-Based Compensation

3 Months Ended

Mar. 31, 2020

. Stock-Based Compensation

The Company recognized stock-based compensation expense on all employee and

non-employee

awards as follows:


	For the three months ended March 31,
(in thousands)	2020		2019
Research and development	$	530	$	433
General and administrative		1,410		1,023

Stock-based compensation expense	$	1,940	$	1,456

The Company granted an aggregate of 896,000 stock options during the three months ended March 31, 2020 with a weighted-average grant date fair value of $2.64 per share. The Company granted an aggregate of 1,496,333 stock options during the three months ended March 31, 2019 with a weighted average grant date fair value of $1.62 per share.

On January 6, 2019, the Company paid an accrued annual performance bonus by issuing 446,428 shares of common stock.

For the three months ended March 31, 2020 and 2019, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:


	For the three months ended March 31 ,
	2020		2019
Risk-free interest rate		0.50 - 1.68%		2.28 - 2.53%
Expected life in years		6 - 6.25		6 - 6.25
Expected volatility		71.11 - 73.01%		78.87 - 85.00%
Expected dividend yield		0%		0%

Stock option activity under the Company’s stock option plan for the three months ended March 31, 2020 is as follows:


(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding, December 31, 2019		5,842,879		$	3.21
Granted		896,000			4.17
Exercised		(2,333	)		1.87
Cancelled		(59,667	)		4.67

Outstanding, March 31, 2020		6,676,879		$	3.95		8.15	$	864

Options exercisable, March 31, 2020		3,024,728		$	4.05		6.83	$	509

Options exercisable, December 31, 2019		2,765,357		$	4.39		6.70	$	3,603

Options available for future grant		1,066,275

At March 31, 2020, total unrecognized compensation costs related to unvested stock options outstanding amounted to $10.1 million. The cost is expected to be recognized over a weighted-average period of 1.78 years.

A summary of the status of unvested restricted stock for the

three

months ended March 31, 2020 is as follows:


	Number of Shares		Weighted-Average Grant Date Fair Value
Non-vested, December 31, 201 9		939,636	$	2.93
Granted		555,900		4.21
Vested		—		—
Cancelled		—		—

Non-vested, March 31, 2020		1,495,536	$	3.41

At March 31, 2020, total unrecognized compensation costs related to unvested restricted stock outstanding amounted to $4.5 million. The cost is expected to be recognized over a weighted-average period of 1.59 years.