STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 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 March 31,
	2019		2018
Cost of sales	$	—	$	14
Research and development expense	273		53
Selling, general and administrative expense	2,429		1,909
Restructuring	—		258
Total	$	2,702	$	2,234