Equity Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Equity Award Activity

The activity related to equity awards, which are comprised of stock options, during the six months ended June 30, 2021 is summarized as follows:

	Equity Awards			Weighted- average Exercise Price per Share		Weighted- average Remaining Contractual Term(1) (years)		Aggregate Intrinsic Value(2) (millions)
Outstanding at December 31, 2020		4,121,666		$	8.67
Granted		562,329		$	4.96
Exercised		(29,379	)	$	5.23
Cancelled/forfeited		(569,549	)	$	9.21
Outstanding at June 30, 2021		4,085,067		$	8.10		8.3	$	0.2
Exercisable at June 30, 2021		1,107,878		$	16.71		5.7	$	-

⁽¹⁾ Represents the weighted-average remaining contractual term of stock options.

⁽²⁾ Aggregate intrinsic value represents the product of the number of equity awards outstanding or equity awards exercisable multiplied by the difference between the Company’s closing stock price per share on the last trading day of the period, which was $4.28 as of June 30, 2021, and the exercise price.

Share-based Compensation Expense

The classification of share-based compensation expense is summarized as follows (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Selling, general and administrative	$	977	$	626	$	1,817	$	1,470
Research and development		47		964		323		2,527
Total share-based compensation expense	$	1,024	$	1,590	$	2,140	$	3,997