Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation Expense Recognized in the Consolidated Statements of Operations

During the three months ended March 31, 2020 and 2019, the Company recognized the following stock-based compensation expense (in thousands):

	Three Months Ended
	March 31,
	2020		2019
Research and development	$	106	$	983
General and administrative		374		1,740
Total	$	480	$	2,723
	Three Months Ended
	March 31,
	2020		2019
Stock options	$	366	$	1,977
Restricted stock units		114		726
Employee stock purchase plan		-		20
Total	$	480	$	2,723

Stock Option Activity

The following table summarizes the stock option activity for the three months ended March 31, 2020:

	Shares			Weighted- Average Exercise Price
Outstanding at December 31, 2019		177,768		$	223.53
Canceled		(29,514	)	$	265.42
Outstanding at March 31, 2020		148,254		$	215.20
Exercisable at March 31, 2020		113,255		$	253.33

Summary of Restricted and Performance Stock Units Activity

The following table summarizes the restricted stock unit, or RSU, and performance stock unit, or PSU, activity for the three months ended March 31, 2020:

	Shares			Weighted- Average Grant Date Fair Value
Unvested at December 31, 2019		91,981		$	28.62
Canceled		(19,845	)	$	34.56
Vested/Released		(22,363	)	$	27.03
Unvested at March 31, 2020		49,773		$	26.97