STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock-based compensation expense recognized for stock options, stock awards, restricted stock units and the Company's employee stock purchase program (ESPP)

The following table presents stock-based compensation expense recognized for stock options, stock awards, RSUs, PSUs and the Company’s ESPP in the Company’s Condensed Consolidated Statements of Operations (in thousands): 

	Three Months Ended September 30,					Nine Months Ended September 30,
	2019		2018			2019		2018
Cost of sales	$	28	$	—		$	78	$	30
Research and development expense	165		270			514		337
Selling, general and administrative expense	2,811		2,674			7,748		7,523
Restructuring	—		(173		)	—		2,385
Total	$	3,004	$	2,771		$	8,340	$	10,275