Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of stock-based compensation expense recognized

Stock-based compensation expense recognized in the consolidated statements of operations is summarized below:

	Year Ended December 31,
(in thousands)	2020		2019		2018
Cost of goods sold	$	2,820	$	2,091	$	1,140
Sales and marketing	1,821		1,953		1,244
General and administrative	7,333		6,990		4,990
Research and development	2,101		1,458		1,344
Total stock-based compensation expense	$	14,075	$	12,492	$	8,718

Schedule of option activity

A summary of option activity for 2020 is presented below:

	Total Stock Options	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Balance at January 1, 2020	272,224	$	17.44
Options granted	2,027,744	$	19.44
Options exercised	(8,868)	$	8.72
Options cancelled and forfeited	(715,881)	$	19.47
Outstanding at December 31, 2020	1,575,219	$	19.03	4.8	229,390
Exercisable at December 31, 2020	1,271,041	$	19.72	3.8	228,958

Summary of restricted stock awards activity

A summary of restricted stock awards and restricted stock units activity for 2020 is presented below:

	Shares	Weighted- Average Grant Date Fair Value Per Share
Nonvested balance at January 1, 2020	1,031,772	$	15.20
Granted	786,006	$	15.00
Vested	(610,804)	$	12.45
Forfeited	(99,108)	$	15.53
Nonvested balance at December 31, 2020	1,107,866	$	16.58

A summary of performance restricted stock award activity for 2020 is presented below:

	Shares	Weighted- Average Grant Date Fair Value Per Share
Nonvested balance at January 1, 2020	226,010	$	16.62
Granted	9,767	$	16.40
Vested	(235,777)	$	16.40
Forfeited	—	$	—
Nonvested balance at December 31, 2020	—	$	—

A summary of TSR Award activity for 2020 is presented below:

	Shares	Weighted- Average Grant Date Fair Value Per Share
Nonvested balance at January 1, 2020	306,230	$	30.56
Granted	220,971	$	23.43
Vested	—	$	—
Forfeited	(35,430)	$	27.47
Nonvested balance at December 31, 2020	491,771	$	27.58

Schedule of valuation model

The table below summarizes the key weighted-average assumptions used in valuing stock options granted:

	Year Ended December 31, 2020
Expected volatility	71.1	%
Risk-free interest rate	0.3	%
Expected life (in years)	3.5
Expected dividend yield	—

The fair value of these awards are based on a Monte Carlo Simulation valuation model with the following assumptions:

	Year Ended December 31,
	2020		2019		2018
Expected volatility	53.3	%	71.7	%	84.3	%
Risk-free interest rate	0.7	%	2.4	%	2.4	%
Expected life (in years)	2.8		2.9		2.8
Expected dividend yield	—		—		—