Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options Activity

The following is a summary of stock option activity during the six months ended June 30, 2020:

	Options Outstanding
	Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
Balance—January 1, 2020		1,862,569		$	9.09		8.64	$	99
Options granted		—		$	—		—	$	—
Options exercised		—		$	—		—	$	—
Options cancelled		(150,648	)	$	8.98		—	$	—
Balance—June 30, 2020		1,711,921		$	9.10		7.88	$	58
Exercisable as of  June 30, 2020		1,039,505		$	8.91		7.53	$	58
Vested and expected to vest as of June 30, 2020		1,711,921		$	9.10		7.88	$	60

Summary of Restricted Stock Award Activity

A summary of restricted stock award activity within the Company’s equity plans and changes for the six months ended June 30, 2020 is as follows:

Restricted Stock Awards	Shares			Weighted Average Grant- Date Fair Value
Nonvested at January 1, 2020		2,601,972		$	18.21
Granted		573,509		$	3.30
Vested		(346,859	)	$	16.54
Forfeited		(505,695	)	$	17.88
Nonvested at June 30, 2020		2,322,927		$	16.23

Summary of Total Stock-based Compensation Expense by Function

The following table summarizes the total stock-based compensation expense by function for the three and six months ended June 30, 2020 and 2019:

	Three Months Ended June 30,					Six Months Ended June 30,
	2019		2020			2019		2020
	(in thousands)					(in thousands)
Sales and distribution expenses	$	2,409	$	(579	)	$	2,797	$	1,013
Research and development expenses		1,872		1,179			2,032		2,452
General and administrative expenses		7,592		4,571			8,544		9,145
Total stock-based compensation expense	$	11,873	$	5,171		$	13,373	$	12,610