Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 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	926,840		2.78
Exercised	—		—
Canceled	(68,214)		85.89
Options Outstanding at September 30, 2019	1,724,758		45.15	8.2
Options Vested and Expected to Vest at September 30, 2019	1,585,308		48.71	8.1
Options Exercisable at September 30, 2019	551,716		127.95	5.6
Shares Available for Grant Under the 2008 Plan	398,707

Schedule of stock-based compensation expense

	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
	(In thousands)				(In thousands)
Research and development	$	330	$	799	$	1,740	$	3,088
General and administrative		377		994		2,124		3,241
Total stock-based compensation expense	$	707	$	1,793	$	3,864	$	6,329

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

	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
Expected stock price volatility	91	%	85	%	91	%	73 - 85	%
Expected option term	6.0	Years	6.0	Years	6.0	Years	6.0	Years
Risk-free interest rate	1.6  -1.9	%	2.8	%	1.6 - 2.5	%	2.8 - 3.0	%
Expected dividend yield	None		None		None		None