Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options Activity

The following is a summary of stock options activity during the six months ended June 30, 2019:

	Options Outstanding
	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
Balance—January 1,  2019		1,867,747		$	9.01	9.64		$	19,573,295
Options granted		131,905		$	10.00
Options exercised		(44	)	$	4.14			$	—
Options cancelled		(104,746	)	$	8.23
Balance—June 30, 2019		1,894,862		$	9.14		9.24	$	596,194
Exercisable as of June 30, 2019		201,770		$	6.21		7.56	$	397,416
Vested and expected to vest as of June 30, 2019		1,894,862		$	9.14		9.24	$	596,194

Summary of Weighted Average Assumptions Used in Black-Scholes Option-Pricing Model to Determine Grant Fair Value

The following are weighted average assumptions used in the Black-Scholes option-pricing model to determine grant fair value:

	June 30, 2018			June 30, 2019
	Weighted- Average			Weighted- Average
Expected term (in years)		0.00			5.73
Volatility		0.00	%		66.04	%
Risk-free interest rate		0.00	%		1.92	%
Dividend Yield		0.000			5.94

Summary of Restricted Stock Activity

A summary of restricted stock activity within the Company’s equity plans and changes for the six months ended June 30, 2019, is as follows:

Restricted Stock Awards	Shares			Weighted Average Grant- Date Fair Value
Nonvested at January 1, 2019		—		$	—
Granted		2,560,148		$	19.26
Vested		—		$	—
Forfeited		(69,141	)	$	19.50
Nonvested at June 30, 2019		2,491,007		$	19.25

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, 2018 and 2019:

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2019		2018		2019
	(in thousands)				(in thousands)
Cost of goods sold	$	—	$	—	$	—	$	—
Sales and distribution expenses		2		528		6		916
Research and development expenses		7		390		13		550
General and administrative expenses		168		1,701		322		2,653
Total stock-based compensation expense	$	177	$	2,619	$	341	$	4,119