EQUITY- BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2020

EQUITY- BASED COMPENSATION

Summary of changes in unvested restricted stock

	Unvested RSUs
		Weighted
		Average
	Number of	Grant-date
	Shares	Fair Value
	in thousands	$ per share
Unvested at December 31, 2018	—	$	—
Granted	1,301	$	2.21
Vested	(100)	$	2.02
Forfeited	(250)	$	2.02
Unvested at December 31, 2019	951	$	2.15
Granted	2,885	$	0.71
Vested	(325)	$	1.07
Forfeited	(573)	$	1.90
Unvested at December 31,  2020	2,938	$	0.85

Schedule of stock option activity

				Weighted
		Weighted		Average
		Average		Remaining		Aggregate
	Number of	Exercise		Contractual		Intrinsic
	Options	Price		Term		Value
	in thousands	$ per share
Outstanding at December 31, 2017	8,157	$	1.28
Granted	1,632	$	2.64
Exercised	(613)	$	0.87
Expired / cancelled	(504)	$	1.71
Outstanding at December 31, 2018	8,672	$	1.54
Granted	600	$	2.07
Exercised	(75)	$	0.93
Forfeited	(1,360)	$	2.09
Outstanding at December 31, 2019	7,837	$	1.49
Exercised	(399)	$	1.04
Forfeited	(169)	$	1.83
Expired	(688)	$	1.51
Outstanding December 31, 2020	6,581	$	1.50	3.9	years	$	3,983
Exercisable at December 31, 2020	5,737	$	1.51	3.7	years	$	4,325

Schedule of fair value assumptions

	2019		2018
Risk-free interest rate (weighted average)	1.54	%	2.77	%
Expected dividend yield	—	%	—	%
Expected stock price volatility	70	%	90	%
Expected life of options (weighted average)	5.15	years	5.61	years

Schedule of compensation costs related to restricted stock and stock options

	Year Ended
	December 31,
	2020		2019		2018
Sales, general, and administrative	$	1,526	$	3,166	$	1,341
Research and Development		128		374		1,846
Total restricted stock and stock option compensation	$	1,654	$	3,540	$	3,187