Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Stock-Based Compensation

Summary of stock option activity

		Weighted		Weighted
		Average		Average
		Exercise		Remaining
		Price		Contractual
	Shares	Per Share		Term (In Years)
Options Outstanding at December 31, 2018	866,132	$	93.70	7.1
Granted	900		4.88
Exercised	—		—
Canceled	(30,928)		125.69
Options Outstanding at March 31, 2019	836,104		92.42	7.0
Options Vested and Expected to Vest at March 31, 2019	800,868		95.77	6.9
Options Exercisable at March 31, 2019	416,737		163.47	5.2
Shares Available for Grant Under the 2008 Plan	387,138

Schedule of stock-based compensation expense

	Three months ended March 31,
	2019		2018
	(In thousands)
Research and development	$	756	$	1,311
General and administrative		937		1,177
Total stock-based compensation expense	$	1,693	$	2,488

Schedule of assumptions used for the fair value of employee stock options granted

	Three months ended March 31,
	2019		2018
Expected stock price volatility	91	%	73	%
Expected option term	6.0	Years	6.0	Years
Risk-free interest rate	2.5	%	2.8	%
Expected dividend yield	None		None