(9) Stock-Based Compensation

A summary of stock option activity for the three months ended March 31, 2020 is as follows:


		Weighted		Weighted
		Average		Average
		Exercise		Remaining
		Price		Contractual
	Shares	Per Share		Term (In Years)
Options Outstanding at December 31, 2019	1,699,202	$	44.87	8.0
Granted	2,750	$	1.66
Exercised	—		—
Canceled	(43,811)	$	50.59
Options Outstanding at March 31, 2020	1,658,141	$	44.65	7.8
Options Vested and Expected to Vest at March 31, 2020	1,585,639	$	46.50	7.8
Options Exercisable at March 31, 2020	576,042	$	118.98	5.6
Shares Available for Grant Under the 2008 Plan	465,324

The weighted average grant-date fair value of stock options granted during the three month period ended March 31, 2020 was $1.23. Stock-based compensation expense for the three months ended March 31, 2020 and 2019 was recorded as follows:


	Three months ended March 31,
	2020		2019
	(In thousands)
Research and development	$	310	$	756
General and administrative		377		937
Total stock-based compensation expense	$	687	$	1,693

The fair values of employee and director stock options granted during the three months ended March 31, 2020 and 2019 were valued using the Black-Scholes option pricing model with the following assumptions:


	Three months ended March 31,
	2020		2019
Expected stock price volatility	91	%	91	%
Expected option term	6.0	Years	6.0	Years
Risk-free interest rate	0.6	%	2.5	%
Expected dividend yield	None		None